1 Install grml to harddisk:
5 Notice: You can pre-select the partition for the partition selector
6 and mbr dialogs inside grml2hd using:
7 # grml2hd /dev/hda1 -mbr /dev/hda
9 See: man grml2hd + http://grml.org/grml2hd/
11 Install grml on software RAID level 1:
13 Create /dev/md0 (and some more /dev/md* devices) first of all:
14 # cd /dev && MAKEDEV dev
17 # mdadm --create --verbose /dev/md0 --level=raid1 \
18 --raid-devices=2 /dev/hda1 /dev/hdc1
20 Finally install grml on it:
21 # SWRAID='mbr-only' grml2hd /dev/md0 -mbr /dev/md0
23 See: man grml2hd + http://grml.org/grml2hd/
25 Install grml in non interactive mode with grml2hd:
27 Adjust configuration as needed:
28 # vim /etc/grml2hd/config
32 # GRML2HD_NONINTERACTIVE=yes grml2hd
38 Use with care and only if you really know what you are doing!
40 See: man grml2hd + http://grml.org/grml2hd/
46 Deactivate error correction of zsh:
50 Run zsh-help for more information regarding zsh.
52 Disable automatic setting of title in GNU screen:
56 Set it manually e.g. via:
58 % screen -X title foobar
60 Run zsh-help for more information regarding zsh.
62 Do not use menu completion in zsh:
66 Run zsh-help for more information regarding zsh.
68 Run GNU screen with grml-configuration:
74 % screen -c /etc/grml/screenrc
76 Print out grml-version:
84 Configure mutt-ng / muttng:
88 Set up Inode-PPTP connection:
92 # grml-pptp-xdsl-students
94 Set up VPN / WLAN connection at TUG (TU Graz):
96 Set ESSID and request for ip-address via DHCP:
97 # iwconfig $DEVICE essid tug
100 Now run the main script:
103 After running the script an init script is available:
105 # /etc/init.d/vpnctug [start|stop]
107 Set up PPTP connection at VCG (Virtual Campus Graz):
117 # grml-vpn -k 2005 add 1000 192.168.20.1 192.168.20.2
121 Use encrypted files / partitions:
123 # grml-crypt <options>
129 # grml-crypt format /mnt/external1/encrypted_file /mnt/test
130 # cp big_file /mnt/test
131 # grml-crypt stop /mnt/test
135 # grml-crypt start /mnt/external1/encrypted_file /mnt/test
136 # grml-crypt stop /mnt/test
140 Change resolution of X:
142 % xrandr -s '1024x768'
144 Change resolution of framebuffer:
148 Configure newsreader slrn:
152 Configure grml system:
156 Or directly run scripts:
161 Lock screen (X / console):
165 Press ctrl-alt-x to lock a GNU screen session.
167 Change wallpaper in X:
169 % grml-wallpaper <press-tab>
171 Start X window system (XFree86 / Xorg / X.org):
173 % grml-x $WINDOWMANAGER
178 % grml-x -mode '1024x768' wmii
179 % grml-x -nosync wm-ng
181 Collect hardware information:
185 or run as root to collect some more information:
189 will generate a file named info.tar.bz2.
191 Configure hardware detection features of harddisk installation:
195 or manually edit /etc/grml/autoconfig[.small]
197 See: man grml-autoconfig
199 Bootoptions / cheatcodes / bootparams for booting grml:
201 On the grml-ISO if not running grml:
202 % less /cdrom/GRML/grml-cheatcodes.txt
205 % most /usr/share/doc/grml-docs/grml-cheatcodes.txt.gz
207 Report bugs to Debian's Bug Tracking System (BTS):
209 % reportbug --bts debian
211 or adjust /etc/reportbug.conf to your needs.
215 http://grml.org/bugs/
216 http://www.debian.org/Bugs/
218 Offline documentation:
222 Online documentation:
225 http://grml.org/docs/
226 http://wiki.grml.org/doku.php
228 Mount ntfs partition (read-write):
231 # ntfsmount /dev/hda1 /mnt/hda1
233 Overwrite specific file on an NTFS partition:
235 ntfscp /dev/hda1 /tmp/file_source path/to/file_target
237 Resize an NTFS partition:
243 ntfsresize -n -s 10G /dev/hda1 # testcase
244 ntfsresize -s 10G /dev/hda1 # testing was successfull, now really resize partition
245 cfdisk /dev/hda # delete partition hda1, create new one with 10000MB and fs-type 07 (NTFS)
247 Modify resolution for intel graphic chipsets:
253 # 915resolution 4d 1400 1050
255 Connect bluetooth mouse:
259 ... and press 'connect' button on your bluetooth device.
261 Connect bluetooth headset:
265 ... and press 'connect' button on your bluetooth device.
267 Secure delete file / directory / partition:
273 Also take a look at shred(1), sfill(1) and http://dban.sourceforge.net/
275 Use grml on Samsung X20 laptop:
277 # apt-get install grml-samsung-x20
279 See: http://www.michael-prokop.at/computer/samsung_x20.html
281 Development information regarding grml:
283 http://grml.supersized.org/
287 #grml on irc.freenode.org - http://grml.org/irc/
288 http://grml.org/contact/
290 Join the grml mailinglist:
292 http://grml.org/mailinglist/
296 http://grml.org/donations/
298 Commercial support / system administration / adjusted live-cds:
300 grml-solutions: http://grml.org/solutions/
302 Information regarding the kernel provided by grml:
304 http://grml.org/kernel/
306 SMTP command-line test tool:
312 % swaks -s $MAILSERVER -tlsc -a -au $ACCOUNT -ap $PASSWORD -f $MAILADRESSE -t $MAILADRESSE
316 NTFS related packages:
322 Modify service through init script:
329 # /etc/init.d/lvm start
333 # jstest /dev/input/js0
337 % mplayer /path/to/movie
339 Use webcam with mplayer:
341 % mplayer tv:// -tv driver=v4l:width=352:height=288:outfmt=yv12:device=/dev/video0
343 Powerful network discovery tool:
347 Grab an entire CD and compress it to Ogg/Vorbis,
348 MP3, FLAC, Ogg/Speex and/or MPP/MP+(Musepack) format:
352 Show a console session in several terminals:
356 Switch behaviour of caps lock key:
360 grep with Perl-compatible regular expressions:
364 ncp: a fast file copy tool for LANs
369 Remote (receive file):
372 utility for sorting records in complex ways:
376 a smaller, cheaper, faster SED implementation:
384 See: http://grml.org/zsh/
386 zsh reference card for grml system:
389 /usr/share/doc/grml-docs/zsh/grml-zsh-refcard.pdf.gz
393 % for i in foo* ; do mv "$i" "bar${i/foo}" ; done
395 % prename 's/foo/bar/' foo*
397 % zmv 'foo(*)' 'bar$1'
399 Test TFT / LCD display:
407 Improved grep version:
411 Grep with highlighting:
413 % grep --color=auto ...
416 Extract matches when grepping:
419 % ifconfig | grepc 'inet addr:(.*?)\s'
420 % ifconfig | glark --extract-matches 'inet addr:(.*?)\s'
422 Output text as sound:
425 % xsay # when running X and text selected via mouse
427 Adjust a grml harddisk (grml2hd) installation:
431 Get information on movie files:
433 % tcprobe -i file.avi
435 Get an overview of your image files:
437 % convert 'vid:*.jpg' thumbnails.jpg
439 List all standard defines:
441 % gcc -dM -E - < /dev/null
443 Send a mail as reminder:
445 echo "mail -s 'check TODO-list' $MAILADDRESS < /dev/null" | at 23:42
447 ncurses-based presentation tool:
451 See: man tpp and /usr/share/doc/tpp/examples/
453 Use ICQ / Jabber / Yahoo! / AIM / MSN /... on command line:
457 Use IRC on command line:
463 % vimdiff file1 file2
469 Moving between diffs:
479 Hardware monitoring without kernel dependencies:
483 Install grml-iso to usb-stick:
485 % grml2usb grml.iso /mount/point
487 Use mplayer on framebuffer console:
489 % mplayer -vo fbdev ...
491 Use links2 on framebuffer console:
493 % links2 -driver fb ...
495 Switch language / keyboard:
497 * use the bootparam lang to set language environment ($LANG, $LC_ALL, $LANGUAGE)
498 * use the bootparams keyboard / xkeyboard to activate specific keyboard layout
499 Usage example: 'grml lang=us keyboard=de xkeyboard=de'
501 Or run one of the following commands:
505 # loadkeys i386/qwertz/de-latin1-nodeadkeys.kmap.gz # console
508 Switch setting of caps-control key (switch between ctrl + shift) on keyboard:
512 Mount usb device / usb stick:
514 % mount /mnt/external1 # corresponds to /dev/sda1
516 % mount /mnt/external # corresponds to /dev/sda
518 Install Sun Java packages:
520 Download j2re.bin-file from http://java.sun.com/downloads/index.html and run
522 # apt-get install java-package
523 # fakeroot make-jpkg j2re-*.bin
524 # dpkg -i sun-j2re*.deb
525 # update-alternatives --config java
529 ddrescue is an improved version of dd which tries to read and
530 if it fails it will go on with the next sectors, where tools
537 How to make an audio file (e.g. Musepack format) out of a DVD track:
539 % mkfifo /tmp/fifo.wav
540 % mppenc /tmp/fifo.wav track06.mpc &
541 % mplayer -vo null -vc null -ao pcm:fast:file=/tmp/fifo.wav -dvd-device /dev/dvd dvd://1 -chapter 6-6
543 Adjust the mppenc line with the encoder you would like to use,
544 for example 'oggenc -o track06.ogg /tmp/fifo.wav' for ogg files.
548 % mplayer -vo null -dumpaudio -dumpfile track06.raw -aid N -dvd-device /dev/dvd dvd://1 -chapter 6-6
549 to extract audio without processing, where 'N' is the corresponding audio channel (see 'man mplayer')
551 Usage example for getting a PCM/wave file from audio channel 128:
552 % mplayer -vo null -vc null -ao pcm:fast:file=track06.wav -aid 128 -dvd-device /dev/dvd dvd://6
554 Create simple chroot:
556 # make_chroot_jail $USERNAME
558 Convert DOS formated file to unix format:
560 sed 's/.$//' dosfile > unixfile # assumes that all lines end with CR/LF
561 sed 's/^M$//' dosfile > unixfile # in bash/tcsh, press Ctrl-V then Ctrl-M
562 sed 's/\x0D$//' dosfile > unixfile # gsed 3.02.80, but top script is easier
563 awk '{sub(/\r$/,"");print}' # assumes EACH line ends with Ctrl-M
564 gawk -v BINMODE="w" '1' infile >outfile # in DOS environment; cannot be done with
565 # DOS versions of awk, other than gawk
566 tr -d \r < dosfile > unixfile # GNU tr version 1.22 or higher
567 tr -d '\015' < dosfile > unixfile # use octal value for "\r" (see man ascii)
568 tr -d '[\015\032]' < dosfile > unixfile # sometimes ^Z is appended to DOS-files
569 vim -c ":set ff=unix" -c ":wq" file # convert using vim
570 vim -c "se ff=dos|x" file # ... and even shorter ;)
571 recode ibmpc..lat1 file # convert using recode
572 echo -e "s/\r//g" > dos2unix.sed; sed -f dos2unix.sed < dosfile > unixfile
574 Save live audio stream to file:
576 % mplayer -ao pcm:file=$FILE
580 % mencoder mms://file.wmv -o $FILE -ovc copy -oac copy
584 % mimms mms://file.wmv
590 % avimerge -i *.avi -o blub.avi
594 % cat *.mpg > blub.mpg
598 % mencoder file1.wmv -ovc lavc -oac lavc -ofps 25 -srate 48000 -mc 0 -noskip -forceidx -o file1.avi
599 % mencoder file2.wmv -ovc lavc -oac lavc -ofps 25 -srate 48000 -mc 0 -noskip -forceidx -o file2.avi
600 % avimerge -i file1.avi file2.avi -o blub.avi
602 Display MS-Word file:
604 % strings file.doc | fmt | less
610 Convert MS-Word file to postscript:
612 % antiword -p a4 file.doc > file.ps
614 Convert manual to postscript:
616 % zcat /usr/share/man/man1/zsh.1.gz | groff -man > zsh.1.ps
618 % man -t zsh > zsh.ps
622 % dd if=/dev/mem bs=1k skip=768 count=256 2>/dev/null | strings -n 8
624 Read HTTP via netcat:
626 echo "GET / HTTP/1.0\r\n\r\n" | netcat $DOMAIN 80
628 Get X ressources for specific program:
630 % xrdb -q |grep -i xterm
632 Get windowid of specific X-window:
634 % xwininfo -int | grep "Window id:" | cut -d ' ' -f 4
636 Get titel of specific X-window:
640 check locale - LC_MESSAGES:
642 % locale -ck LC_MESSAGES
644 Create random password:
648 % dd if=/dev/urandom bs=14 count=1 | hexdump | cut -c 9-
650 Get tarballs of various Linux Kernel trees:
653 to get the current stable 2.6 release
656 to get a list of all supported trees
658 Transfer your SSH public key to another host:
660 % ssh-keygen # ssh-keygen / ssh-key-gen: if you don't have a key yet
662 % ssh-copy-id -i ~/.ssh/id_rsa.pub user@remote-system
664 % cat $HOME/.ssh/id_rsa.pub | ssh user@remote-system 'cat >> .ssh/authorized_keys'
666 Update /etc/fstab entries:
670 See "man grml-rebuildfstab" for more details about
671 generation of /etc/fstab (including stuff like
672 fs LABELs / UUIDs,...).
674 Fetch and potentially change SCSI device parameters:
680 reclaim disk space by linking identical files together:
684 Find and remove duplicate files:
688 Perform layer 2 attacks:
694 Guess PC-type hard disk partitions / partition table:
698 Perform a standard scan:
701 Write back the guessed table:
702 # gpart -W /dev/ice /dev/ice
704 Develop, test and use exploit code with the Metasploit Framework:
707 wget http://framework-mirrors.metasploit.com/msf/downloader/framework-3.0.tar.gz
708 unp framework-3.0.tar.gz
712 Useful documentation:
714 % w3m /usr/share/doc/Debian/reference/reference.en.html
716 % xpdf =(zcat /usr/share/doc/Debian/reference/reference.en.pdf.gz)
718 http://grml.org/docs/ grml Documentation
719 http://wiki.grml.org/ grml Wiki
720 http://www.debian.org/doc/ Debian Documentation
721 http://wiki.debian.org/ Debian Wiki
722 http://www.gentoo.org/doc/en/ Gentoo Documentation
723 http://gentoo-wiki.com/ Gentoo Wiki
724 http://www.tldp.org/ The Linux Documentation Project
728 % fortune debian-hints
732 % fortune debian-hints
733 % dpkg -L funny-manpages
735 Backup master boot record (MBR):
737 # dd if=/dev/ice of=/tmp/backup_of_mbr bs=512 count=1
739 Backup partition table:
741 # sfdisk -d /dev/hda > hda.out
743 Restore partition table:
745 # sfdisk /dev/hda < hda.out
747 Clone disk via network using netcat:
750 # nc -vlp 30000 > hda1.img
752 # dd if=/dev/hda1 | nc -vq 0 192.168.1.2 30000
754 Adjust blocksize (dd's option bs=...) and include 'gzip -c'
757 # dd if=/dev/hda1 bs=32M | gzip -c | nc -vq 0 192.168.1.2 30000
759 Backup specific directories via cpio and ssh:
761 # for f in directory_list; do find $f >> backup.list done
762 # cpio -v -o --format=newc < backup.list | ssh user@host "cat > backup_device"
766 This one uses CPU cycles on the remote server to compare the files:
767 # ssh target_address cat remotefile | diff - localfile
768 # cat localfile | ssh target_address diff - remotefile
770 This one uses CPU cycles on the local server to compare the files:
771 # ssh target_address cat <localfile "|" diff - remotefile
773 Useful tools for cloning / backups:
775 * dd: convert and copy a file
776 * dd_rescue: copies data from one file (or block device) to another
777 * pcopy: a replacement for dd
778 * partimage: back up and restore disk partitions
779 * dirvish: Disk based virtual image network backup system
780 * devclone: in-place filesystem conversion -- device cloning
781 * ntfsclone: efficiently clone, image, restore or rescue an NTFS
782 * dump: ext2/3 filesystem backup
783 * udpcast: multicast file transfer tool
784 * cpio: copy files to and from archives
785 * pax: read and write file archives and copy directory hierarchies
786 * netcat / ssh / tar / gzip / bzip2: additional helper tools
788 Use grml as a rescue system:
792 * dd: convert and copy a file
793 * ddrescue: copies data from one file or block device to another
794 * partimage: Linux/UNIX utility to save partitions in a compressed image file
795 * cfdisk: Partition a hard drive
796 * nparted: Newt and GNU Parted based disk partition table manipulator
797 * parted-bf: The GNU Parted disk partition resizing program, small version
798 * testdisk: Partition scanner and disk recovery tool
799 * gpart: Guess PC disk partition table, find lost partitions
803 * e2fsprogs: ext2 file system utilities and libraries
804 * e2tools: utilities for manipulating files in an ext2/ext3 filesystem
805 * e2undel: Undelete utility for the ext2 file system
806 * ext2resize: an ext2 filesystem resizer
807 * recover: Undelete files on ext2 partitions
811 * reiser4progs: administration utilities for the Reiser4 filesystem
812 * reiserfsprogs: User-level tools for ReiserFS filesystems
816 * xfsdump: Administrative utilities for the XFS filesystem
817 * xfsprogs: Utilities for managing the XFS filesystem
821 * jfsutils: utilities for managing the JFS filesystem
825 * ntfsprogs: tools for doing neat things in NTFS partitions from Linux
826 * salvage-ntfs: free NTFS data recovery tools
827 * scrounge-ntfs: data recovery program for NTFS file systems
828 * ntfsresize: resize ntfs partitions
830 Get ASCII value of a character with zsh:
832 % char=N ; print $((#char))
834 Convert a collection of mp3 files to wave or cdr using zsh:
836 % for i (./*.mp3){mpg321 --w - $i > ${i:r}.wav}
838 Convert images (foo.gif to foo.png) using zsh:
840 % for i in **/*.gif; convert $i $i:r.png
842 Remove all "non txt" files using zsh:
846 Remote Shell Using SSH:
849 % ssh -NR 3333:localhost:22 user@yourhost
852 % ssh user@localhost -p 3333
854 Reverse Shell with Netcat:
857 % netcat -v -l -p 3333 -e /bin/sh
860 % netcat 192.168.0.1 3333
862 Reverse Shell via SSH:
864 local host (inside the network):
865 % ssh -NR 1234:localhost:22 remote_host
867 remote host (outside the network):
868 % ssh localhost -p 1234
870 Remove empty directories with zsh:
872 % rmdir ./**/*(/od) 2> /dev/null
874 Find all the empty directories in a tree with zsh:
878 Find all files without a valid owner and change ownership with zsh:
880 % chmod user /**/*(D^u:${(j.:u:.)${(f)"$(</etc/passwd)"}%%:*}:)
882 Display the 5-10 last modified files with zsh:
884 % print -rl -- /path/to/dir/**/*(D.om[5,10])
886 Find and list the ten newest files in directories and subdirs (recursive) with zsh:
888 % print -rl -- **/*(Dom[1,10])
890 Find most recent file in a directory with zsh:
892 % setopt dotglob ; print directory/**/*(om[1])
894 Tunnel all traffic through an external server:
896 % ssh -ND 3333 username@external.machine
898 Then set the SOCKS4/5 proxy to localhost:3333.
899 Check whether it's working by surfing e.g. to checkip.dyndns.org
901 Tunnel everything through SSH via tsocks:
903 set up the SSH proxy on the client side:
905 % ssh -ND 3333 user@remote.host.example.com
907 Adjust /etc/tsocks.conf afterwards (delete all other lines):
912 For programs who natively support proxying connections (e.g. Mozilla
913 Firefox) you can now set the proxy address to localhost port 3333.
915 All other programs which's connections you want to tunnel through your
916 external host are prefixed with tsocks, e.g.:
918 % tsocks netcat example.com 80
919 % tsocks irssi -c irc.quakenet.eu.org -p 6667
921 If you call tsocks without parameters it executes a shell witht the
922 LD_PRELOAD environment variable already set and exported.
924 smartctl - control and monitor utility for harddisks using Self-Monitoring,
925 Analysis and Reporting Technology (SMART):
927 # smartctl --all /dev/ice
929 If you want to use smartctl on S-ATA (sata) disks use:
931 # smartctl -d ata --all /dev/sda
934 # smartctl -t offline /dev/ice
937 # smartctl -t short /dev/ice
939 Display results of test:
940 # smartctl -l selftest /dev/ice
942 Query device information:
943 # smartctl -i /dev/ice
945 Mount a BSD / Solaris partition:
947 # mount -t ufs -o ufstype=ufs2 /dev/hda1 /mnt/hda1
949 Use ufstype 44bsd for FreeBSD, NetBSD, OpenBSD (read-write).
950 Use ufstype ufs2 for >= FreeBSD 5.x (read-only).
951 Use ufstype sun for SunOS (Solaris) (read-write).
952 Use ufstype sunx86 for SunOS for Intel (Solarisx86) (read-write).
954 See /usr/share/doc/linux-doc-$(uname -r)/Documentation/filesystems/ufs.txt.gz
957 Read BIOS (and or BIOS) password:
959 # dd if=/dev/mem bs=512 skip=2 count=1 | hexdump -C | head
961 Clone one of the kernel trees via git:
963 git clone rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
964 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
965 This path defines the tree. See http://kernel.org/git/ for an overview.
967 Mount filesystems over ssh protocol:
969 % sshfs user@host:/remote_dir /mnt/test
973 % fusermount -u /mnt/test
975 (Notice: requires fuse kernel module)
977 Install Gentoo using grml:
979 See http://www.gentoo.org/doc/en/altinstall.xml
981 Install (plain) Debian (sarge release) via grml:
983 Assuming you want to install Debian to sda1:
985 mkfs.ext3 /dev/sda1 # make an ext3 filesystem on /dev/sda1
986 mount -o rw,suid,dev /dev/sda1 /mnt/test # now mount the new partition
987 debootstrap sarge /mnt/test ftp://ftp.tugraz.at/mirror/debian # get main packages from a debian-mirror
988 chroot /mnt/test /bin/bash # let's chroot into the new system
989 mount -t devpts none /dev/pts # ...otherwise running base-config might fail ("Terminated" or "openpty failed")
990 mount -t proc none /proc # make sure we also have a mounted /proc
991 base-config # now configure some main settings
992 vi /etc/mkinitrd/mkinitrd.conf # adjust $ROOT (to /dev/sda1) for your new partition, autodetection will fail in chroot
993 cd /dev ; ./MAKEDEV generic # make sure we have all necessary devices for lilo
994 apt-get install lilo linux-image-2.6.12-1-386 # install lilo and a kernel which fits your needs
995 cp /usr/share/doc/lilo/examples/conf.sample /etc/lilo.conf # let's use a template
996 vi /etc/lilo.conf && lilo # adjust the file for your needs and run lilo afterwards
997 umount /proc ; umount /dev/pts # we do not need them any more
998 exit # now leave chroot
999 cp /etc/hosts /etc/fstab /mnt/test/etc/ # you might want to take the existing files...
1000 cp /etc/network/interfaces /mnt/test/etc/network/ # ...from the running grml system for your new system
1001 umount /mnt/test && reboot # unmount partition and reboot...
1003 See also: http://www.debian.org/releases/stable/i386/apcs04.html.en
1004 Avoid all of the above steps - use grml-debootstrap(8) instead!
1006 Install (plain) Debian (etch release) via grml
1008 Assuming you want to install Debian to sda1:
1010 mkfs.ext3 /dev/sda1 # make an ext3 filesystem on /dev/sda1
1011 mount -o rw,suid,dev /dev/sda1 /mnt/test # now mount the new partition
1012 debootstrap etch /mnt/test ftp://ftp.tugraz.at/mirror/debian # get main packages from a debian-mirror
1013 chroot /mnt/test /bin/bash # let's chroot into the new system
1014 mount -t proc none /proc # make sure we have a mounted /proc
1015 apt-get install locales console-data # install locales
1016 dpkg-reconfigure locales console-data # adjust locales to your needs
1017 apt-get install vim most zsh screen less initrd-tools file grub \
1018 usbutils pciutils bzip2 sysfsutils dhcp3-client resolvconf \
1019 strace lsof w3m # install useful software
1020 apt-get install linux-headers-2.6-686 linux-image-686 # install current kernel
1022 echo "127.0.0.1 localhost" > /etc/hosts # adjust /etc/hosts and network:
1023 cat >> /etc/network/interfaces << EOF
1024 iface lo inet loopback
1025 iface eth0 inet dhcp
1030 ln -sf /usr/share/zoneinfo/Europe/Vienna /etc/localtime # adjust timezone and /etc/fstab:
1031 cat >> /etc/fstab << EOF
1032 sysfs /sys sysfs auto 0 0
1033 proc /proc proc defaults 0 0
1034 /dev/sda1 / ext3 defaults,errors=remount-ro 0 1
1035 /dev/sda2 none swap sw 0 0
1036 /dev/cdrom /mnt/cdrom0 iso9660 ro,user,noauto 0 0
1038 passwd # set password of user root
1040 mkdir /boot/grub # setup grub
1041 cp /usr/share/doc/grub/examples/menu.lst /boot/grub
1042 cat >> /boot/grub/menu.lst << EOF
1043 title Debian Etch, kernel 2.6.18-3-686 (on /dev/sda1)
1045 kernel /boot/vmlinuz-2.6.18-3-686 root=/dev/sda1 ro
1046 initrd /boot/initrd.img-2.6.18-3-686
1048 vim /boot/grub/menu.lst # adjust grub configuration to your needs
1049 cd /dev && MAKEDEV generic # create default devices
1050 cp -i /usr/lib/grub/i386-pc/* /boot/grub/ # copy stage-files to /boot/grub/
1051 grub install # now install grub, run in grub-cmdline following commands:
1055 umount -a # unmount all filesystems in chroot and finally:
1056 exit # exit the chroot and:
1059 If you want to use lilo instead of grub take a look at
1060 /usr/share/doc/lilo/examples/conf.sample or use the following template:
1062 cat > /etc/lilo.conf << EOF
1063 # This allows booting from any partition on disks with more than 1024 cylinders.
1066 # Specifies the boot device
1069 # Specifies the device that should be mounted as root.
1072 # use Debian on software raid:
1073 # raid-extra-boot=mbr-only
1081 image=/boot/vmlinuz-2.6.18-grml
1085 initrd=/boot/initrd.img-2.6.18-grml
1088 See also: http://www.debian.org/releases/stable/i386/apcs04.html.en
1089 Avoid all of the above steps - use grml-debootstrap(8) instead!
1091 Convert files from Unicode / UTF-8 to ISO:
1093 % iconv -c -f utf8 -t iso-8859-15 < utffile > isofile
1097 % iconv -f iso-8859-15 -t utf8 < isofile > utffile
1099 Assign static setup for network cards (eth0 and eth1) via udev:
1101 First method - manual:
1102 ~~~~~~~~~~~~~~~~~~~~~~
1103 Get information for SYSFS address:
1104 # udevinfo -a -p /sys/class/net/eth0/ | grep address
1106 Then create udev rules:
1107 # cat /etc/udev/network.rules
1109 KERNEL=="eth*", SYSFS{address}=="00:00:00:00:00:01", NAME="wlan0"
1110 KERNEL=="eth*", SYSFS{address}=="00:00:00:00:00:02", NAME="lan0"
1111 # do not match eth* drivers but also e.g. firewire stuff:
1112 ACTION=="add", SUBSYSTEM=="net", SYSFS{address}=="00:00:00:00:00:03", NAME="1394"
1114 Now activate the rules:
1115 # cd /etc/udev/rules.d/ && ln -s ../network.rules z35_network.rules
1117 Unload the drivers, restart udev and load the drivers again to activate
1120 Second method - automatic:
1121 ~~~~~~~~~~~~~~~~~~~~~~~~~~
1122 Run /lib/udev/write_net_rules shipped with recent udev versions:
1124 # INTERFACE=wlan1 /lib/udev/write_net_rules 00:00:00:00:00:04
1126 This command will create /etc/udev/rules.d/z25_persistent-net.rules containing:
1128 SUBSYSTEM=="net", DRIVER=="?*", SYSFS{address}=="00:00:00:00:00:04", NAME=wlan1
1130 See /usr/share/doc/udev/writing_udev_rules/index.html for more information.
1132 Change the suffix from *.sh to *.pl using zsh:
1135 % zmv -W '*.sh' '*.pl'
1137 Generate SSL certificate:
1139 Create self signed certificate (adjust /etc/ssl/openssl.cnf if necessary):
1140 # openssl req -x509 -newkey rsa:1024 -keyout keyfile -out certfile -days 9999 -nodes
1143 # openssl x509 -in certfile -text
1145 Verify against CA certificate:
1146 # openssl verify -CAfile cacert.crt -verbose -purpose sslserver
1148 Generate 2048bit RSA-key:
1149 # openssl req -new -x509 -keyout pub-sec-key.pem -out pub-sec-key.pem -days 365 -nodes
1151 As before but add request to existing key pub-sec-key.pem:
1152 # openssl req -new -out request.pem -keyin pub-sec-key.pem
1154 Show request request.pem:
1155 # openssl req -text -noout -in request.pem
1157 Verify signature of request request.pem:
1158 # openssl req -verify -noout -in request.pem
1160 Generate SHA1 fingerprint (modulo key) of request.pem:
1161 # openssl req -noout -modulus -in request.pem | openssl sha1 -c
1163 Generate 2048bit RSA-key and put it to pub-sec-key.pem. Save self signed certificate in self-signed-certificate.pem:
1164 # openssl req -x509 -days 365 -newkey rsa:2048 -out self-signed-certificate.pem -keyout pub-sec-key.pem
1166 As before but create self signed certificate based on existing key pub-sec-key.pem:
1167 # openssl req -x509 -days 365 -new -out self-signed-certificate.pem -key pub-sec-key.pem
1169 Generate new request out of existing self signed certificate:
1170 # openssl x509 -x509toreq -in self-signed-certificate.pem -signkey pub-sec-key.pem -out request.pem
1172 Display certificate self-signed-certificate.pem in plaintext:
1173 # openssl x509 -text -noout -md5 -in self-signed-certificate.pem
1175 Check self signed certificate:
1176 # openssl verify -issuer_checks -CAfile self-signed-certificate.pem self-signed-certificate.pem
1178 Estable OpenSSL-connection using self-signed-certificate.pem and display certificate:
1179 # openssl s_client -showcerts -CAfile self-signed-certificate.pem -connect www.example.com:443
1181 Generate ssl-certificate for use with apache2:
1183 export RANDFILE=/dev/random
1184 mkdir /etc/apache2/ssl/
1185 openssl req $@ -new -x509 -days 365 -nodes -out /etc/apache2/ssl/apache.pem -keyout /etc/apache2/ssl/apache.pem
1186 chmod 600 /etc/apache2/ssl/apache.pem
1188 Also take a look at make-ssl-cert (debconf wrapper for openssl):
1190 # /usr/sbin/make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/apache.pem
1192 and mod-ssl-makecert (utility to create SSL certificates in /etc/apache/ssl.*/).
1194 Change Windows NT password(s):
1196 # mount -o rw /mnt/hda1
1197 # cd /mnt/hda1/WINDOWS/system32/config/
1198 # chntpw SAM SECURITY system
1200 Notice: if mounting the partition read-write did not work (check syslog!)
1201 try using mount.ntfs-3g instead: mount.ntfs-3g /dev/hda1 /mnt/hda1
1203 (Be careful with deactivating syskey!)
1205 glark - replacement for grep written in Ruby:
1207 A replacement for (or supplement to) the grep family, glark offers:
1208 Perl compatible regular expressions, highlighting of matches,
1209 context around matches, complex expressions and automatic exclusion
1214 % glark -y keyword file # display only the region that matched, not the entire line
1215 % glark -o format print *.h # search for either "printf" or "format"
1217 More information: man glark
1219 Find CD burning device(s):
1221 General information on CD-ROM:
1222 % cat /proc/sys/dev/cdrom/info
1224 Scan using ATA Packet specific SCSI transport:
1225 # cdrecord -dev=ATA -scanbus
1226 # cdrecord-prodvd -s -scanbus dev=ATA
1228 Get specific information for /dev/ice:
1229 # cdrecord dev=/dev/ice -scanbus
1231 Create devices in /dev on udev:
1233 For example create md devices (/dev/md0, /dev/md1,...):
1234 # cd /dev ; WRITE_ON_UDEV=1 ./MAKEDEV md
1236 Identify network device (NIC):
1238 # ethtool -i $DEVICE
1240 Show NIC statistics:
1242 # ethtool -S $DEVICE
1244 If your NIC shows some aging signs, you may want to be sure:
1246 # ethtool -t $DEVICE
1248 Disable TCP/UDP checksums:
1250 # ethtool -K $DEVICE tx off
1252 grml2hd seems to hang? Getting Squashfs errors? Problems while booting?
1254 Switch to tty12 and take a look at the syslog. If you see something like:
1256 SQUASHFS error: zlib_fs returned unexpected result 0x........
1257 SQUASHFS error: Unable to read cache block [.....]
1258 SQUASHFS error: Unable to read inode [.....]
1260 your ISO/CD-ROM very probably is not ok. Verify it via booting with grml testcd.
1261 Check your CD low-level via running:
1263 # readcd -c2scan dev=/dev/cdrom
1265 If the medium really is ok and it still fails try to boot with deactivated DMA
1266 via using grml nodma at the bootprompt.
1268 Write a Microsoft compatible boot record (MBR) using ms-sys
1270 Write a Windows 2000/XP/2003 MBR to device:
1272 # ms-sys -m /dev/ice
1274 Use a Vodafone 3G Datacard (UMTS) with Linux:
1276 Plug in your vodafone card and check in syslog whether the appropriate
1277 (probably /dev/ttyUSB0 or /dev/noz0) has been created. If so run:
1280 # wvdial --config /etc/wvdial.conf.umts $PROFILE
1283 # gcom -d /dev/ttyUSB0
1284 # wvdial --config /etc/wvdial.conf.umts a1usb
1287 # wvdial --config /etc/wvdial.conf.umts tmnozomi
1290 # wvdial --config /etc/wvdial.conf.umts dreiusb
1292 If you receive invalid DNS nameservers when connecting, like:
1295 --> primary DNS address 10.11.12.13
1296 --> secondary DNS address 10.11.12.14
1298 just provide a working nameserver to resolvconf via:
1300 # echo "nameserver 80.120.17.70" | resolvconf -a ppp0
1302 Notice: some vodafone cards require the nozomi driver (run 'modprobe nozomi' on
1303 your grml system), some other ones require the sierra driver (run
1306 If your device isn't supported by usbserial yet, manually provide vendor and
1307 product ID when loading the usbserial module. Usage example:
1311 Bus 004 Device 008: ID 1199:6813 Sierra Wireless, Inc.
1313 # modprobe usbserial vendor=0x1199 product=0x6813
1315 hdparm - get/set hard disk parameters
1317 Display the identification info that was obtained from the drive at boot time,
1319 # hpdarm -i /dev/ice
1321 Request identification info directly from the drive:
1322 # hpdarm -I /dev/ice
1324 Perform timings of device + cache reads for benchmark and comparison purposes:
1325 # hdparm -tT /dev/ice
1327 bonnie++ - program to test hard drive performance.
1329 # mkdir /mnt/benchmark
1330 # mount /dev/ice /mnt/benchmark
1331 # chmod go+w /mnt/benchmark
1332 # bonnie -u grml -d /mnt/benchmark -s 2000M
1334 Use gizmo with a bluetooth headset:
1336 % DEVICE="/dev/dsp$(awk '/- BT Headset/ {print $1}' /proc/asound/cards)"
1337 % gizmo --mic $DEVICE --speaker $DEVICE
1339 Scan a v4l device for TV stations:
1341 % scantv -c /dev/video0 -C /dev/vbi0 -o ~/.xawtv
1343 Then running xawtv should work:
1347 Run apt-get with timeout of 3 seconds:
1349 # apt-get -o acquire::http::timeout=3 update
1351 Debian GNU/Linux device driver check page
1353 % $BROWSER http://kmuto.jp/debian/hcl/index.cgi
1355 Use dd with status line:
1357 # dd if=/dev/ice conv=noerror,notrunc,sync | buffer -S 100k | dd of=/tmp/file
1359 Generate a 512k file of random data with status bar:
1361 % dd if=/dev/random bs=1024 count=512 | bar -s 512k -of ./random
1363 Install Grub instead of lilo on grml installation (grml2hd):
1368 adjust grub's configuration file menu.lst:
1369 # $EDITOR /boot/grub/menu.lst
1371 now install grub (usage example for /dev/sda1):
1376 Install Ubuntu using grml:
1378 See https://wiki.ubuntu.com/Installation/FromKnoppix
1380 Resize ext2 / ext3 partition:
1382 # tune2fs -O '^has_journal' /dev/iceX # disable journaling
1383 # fsck.ext2 -v -y -f /dev/iceX # check the filesystem
1384 # resize2fs -p /dev/iceX $SIZE # resize it (adjust $SIZE)
1385 # fdisk /dev/ice # adjust partition in partition table
1386 # fsck.ext2 -v -y -f /dev/iceX # check filesystem again
1387 # resize2fs -p /dev/iceX # resize it to maximum
1388 # tune2fs -j /dev/iceX # re-enable journal
1390 Tune ext2 / ext3 filesystem:
1392 Check partition first:
1394 # tune2fs -l /dev/iceX
1396 If you don't see dir_index in the list, then enable it:
1398 # tune2fs -O dir_index /dev/iceX
1400 Now run e2fsck with the -D option to have the directories optimized:
1402 # e2fsck -D /dev/iceX
1404 Notice: since e2fsprogs (1.39-1) filesystems are created with
1405 directory indexing and on-line resizing enabled by default.
1407 Search for printers via network:
1409 # pconf_detect -m NETWORK -i 192.168.0.1/24
1411 Mount a remote directory via webdav (e.g. Mediacenter of GMX):
1413 # mount -t davfs https://mediacenter.gmx.net/ /mnt/test
1415 System-Profiling using oprofile:
1420 # opcontrol --setup --no-vmlinux --event=CPU_CLK_UNHALTED:500000:0:1:1 --separate=library
1425 Now $DO_SOME_TASKS...
1428 # opcontrol --shutdown
1430 Then take a look at the reports using something like e.g.:
1431 # opreport -t 0.5 --exclude-dependent
1432 # opreport -t 0.5 /path/to/executable_to_check
1433 # opannotate -t 0.5 --source --assembly
1435 Install ATI's fglrx driver for Xorg / X.org:
1437 Usually there already exist drivers for the grml-system:
1438 # apt-get update ; apt-get install fglrx-driver fglrx-kernel-`uname -r`
1440 After installing adjust xorg.conf via running:
1441 # aticonfig --initial --input=/etc/X11/xorg.conf
1443 For more information take a look at http://wiki.grml.org/doku.php?id=ati
1445 Install nvidia driver for Xorg / X.org:
1447 Usually there already exist drivers for the grml-system:
1448 # apt-get update ; apt-get install nvidia-glx nvidia-kernel-`uname -r`
1450 Then switch from module nv to nvidia:
1452 # sed -i 's/Driver.*nv.*/Driver "nvidia"/' /etc/X11/xorg.conf
1454 glxgears - a GLX demo that draws three rotating gears
1456 To print frames per second (fps) use:
1457 % glxgears -printfps
1459 You forgot to boot with 'grml noeject noprompt' to avoid
1460 ejecting and prompting for CD removal when rebooting/halting
1471 If you want to avoid only the prompting part, run:
1479 Mount wikipedia local via fuse:
1481 Adjust configuration:
1482 % cat ~/.wikipediafs/config.xml
1485 <article-cache-time>300</article-cache-time>
1489 <dirname>wikipedia-de</dirname>
1490 <host>de.wikipedia.org</host>
1491 <basename>/w/index.php</basename>
1494 <dirname>wikipedia-en</dirname>
1495 <host>en.wikipedia.org</host>
1496 <basename>/w/index.php</basename>
1501 Mount it (/wiki must exist of course):
1502 % mount.wikipediafs /wiki
1503 % cat /wiki/wikipedia-en/Cat
1506 % fusermount -u /wiki
1508 Remote notification on X via osd (on screen display):
1510 Start osd_server.py at your local host (listens on port 1234 by default):
1513 Then login to a $REMOTEHOST
1514 % ssh -R 1234:localhost:1234 $REMOTEHOST
1516 Now send the text to your local display via running something like:
1517 % echo "text to send" | nc localhost 1234
1519 Very useful when you are waiting for a long running job
1520 but want to do something else in the meanwhile:
1522 % ./configure && make && echo "finished compiling" | netcat localhost 1234
1524 You can use this in external programs as well of course. Examples:
1526 Use osd in centericq:
1528 % cat ~/.centericq/external
1537 if [ -x /usr/bin/socat -a -x /bin/netcat ] ; then
1538 CONTACT_CUSTOM_NICK=$(cat ${CONTACT_INFODIR}/info | head -n 46 | tail -n 1)
1539 osd_msg="*** CenterICQ: new ${EVENT_NETWORK} ${EVENT_TYPE} from ${CONTACT_CUSTOM_NICK} ***"
1540 if echo | socat - TCP4:localhost:1234 &>/dev/null ; then
1541 echo "${osd_msg}" | netcat localhost 1234
1545 Use it in the IRC console client irssi via running:
1549 You can even activate the port forwarding by default globally:
1554 RemoteForward 1234 127.0.0.1:1234
1557 Notice: if you get 'ABORT: Requested font not found' make sure the
1558 requested font is available, running 'LANG=C LC_ALL=C osd_server.py...'
1561 Avoid automatical startup of init scripts via invoke-rc.d:
1563 First of all make sure the package policyrcd-script-zg2 (which
1564 provides the /usr/sbin/policy-rc.d interface) is installed.
1566 In policyrcd-script-zg2's configuration file named
1567 /etc/zg-policy-rc.d.conf the script /usr/sbin/grml-policy-rc.d is
1568 defined as the interface for handling invoke-rc.d's startup policy.
1570 grml-policy-rc.d can be configure via /etc/policy-rc.d.conf. By
1571 default you won't notice any differences to Debian's default
1572 behaviour, except that invoke-rc.d won't be executed if a chroot has
1573 been detected (detection: /proc is missing).
1575 If you want to disable automatical startup of newly installed packages
1576 (done via the invoke-rc.d mechanism) just set EXITSTATUS to '101' in
1577 /etc/policy-rc.d.conf.
1579 To restore the default behaviour set EXITSTATUS back to '0' in
1580 /etc/policy-rc.d.conf.
1582 Install VMware-Tools for grml:
1584 First of all make sure a CD-ROM device in VMware is available.
1586 Mount the CD-ROM device to /mnt/cdrom, then unpack and install
1590 unp /mnt/cdrom/vmware-linux-tools.tar.gz
1591 cd vmware-tools-distrib
1594 /etc/init.d/networking stop
1599 /etc/init.d/networking start
1601 In an X terminal, launch the VMware Tools running:
1605 Some important Postfix stuff
1613 Send all messages in the queue:
1617 Send all messages in the queue for a specific site:
1621 Delete a specific message
1622 # postsuper -d 12345678942
1624 Deletes all messages held in the queue for later delivery
1625 # postsuper -d ALL deferred
1627 Mail queues in postfix:
1629 incoming -> mail who just entered the system
1630 active -> mail to be delivered
1631 deferred -> mail to be delivered later because there were problems
1632 hold -> mail that should not be delivered until released from hold
1634 For configuration of postfix take a look at
1635 /etc/postfix/master.cf - man 5 master
1636 /etc/postfix/main.cf - man 5 postconf
1637 and http://www.postfix.org/documentation.html.
1641 mode 4000 - set user ID (suid):
1643 - for executable files: run as the user who owns the file, instead of the
1644 user who runs the file
1645 - for directories: not used
1647 mode 2000 - set group ID (guid):
1649 - for executable files: run as the group who owns the file, instead of the
1650 group of the user who runs the file
1651 - for directories: when a file is created inside the directory, it belongs
1652 to the group of the directory instead of the default group of the user who
1655 mode 1000 - sticky bit:
1657 - for files: not used
1658 - for directories: only the owner of a file can delete or rename the file
1660 Create MySQL database
1662 # apt-get install mysql-client mysql-server
1664 Run 'mysql' as root - create a database with:
1666 create database grml
1668 Give a user access to the database (without password):
1670 grant all on grml.* to mika;
1672 Give a user access to the database (with password):
1674 grant all on grml.* to enrico identified by "PASSWORD";
1676 Setup an HTTPS website:
1678 Create a certificate:
1680 # mkdir /etc/apache2/ssl
1681 # make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache.pem
1683 Create a virtual host on port 443:
1685 <VirtualHost www.foo.invalid:443>
1689 Enable SSL in the VirtualHost:
1692 SSLCertificateFile /etc/apache2/ssl/apache.pem
1694 Enable listening on the HTTPS port (/etc/apache2/ports.conf):
1698 and make sure the SSL module is used:
1702 Useful Apache / Apache2 stuff
1704 Check configuration file via running:
1706 # apache2ctl configtest
1714 # a2enmod modulename
1716 Create tar archive and store it on remote machine:
1718 % tar zcf - /sourcedir | ssh user@targethost "cat >file.tgz"
1720 Pick out and displays images from network traffic:
1724 Install Flash plugin:
1726 # dpkg-reconfigure flashplugin-nonfree
1728 To test a proxy, low level way:
1732 GET http://www.google.com HTTP/1.0 [press enter twice]
1734 Adjust system for use of qemu with kqemu:
1736 Make sure you have all you need:
1737 # aptitude update ; aptitude install qemu kqemu-modules-$(uname -r)
1742 mknod /dev/kqemu c 250 0
1743 chmod 666 /dev/kqemu
1744 chmod 666 /dev/net/tun
1746 Check kqemu support via starting qemu, press
1747 Ctrl-Alt-2 and entering 'info kqemu'.
1749 (High-Load) Debugging related tools:
1751 mpstat # report processors related statistics
1752 iostat # report CPU statistics and input/output statistics for devices and partitions
1753 vmstat # report virtual memory statistics
1754 slabtop # display kernel slab cache information in real time
1755 atsar # system activity report
1756 dstat # versatile tool for generating system resource statistics
1767 Using WPA for network setup manually:
1769 # wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant.conf
1771 Adjust the options and configuration file to your needs.
1772 Also take a look at 'grml-network'.
1774 Start X and lock console via exiting:
1776 % startx 2>~/.xsession-errors &| exit
1778 Which process is writing to disk and/or causes the disk to spin up?
1780 First of all use lsof to check what's going on. Does not help? ->
1782 # echo 1 > /proc/sys/vm/block_dump
1784 The command sets a sysctl to cause the kernel to log all disk
1785 writes. Please notice that there is a lot of data. So please
1786 disable syslogd/syslog-ng before you do this, or you must make
1787 sure that kernel output is not logged.
1789 When you're done, disable block dump using:
1790 # echo 0 > /proc/sys/vm/block_dump
1793 laptop-mode-tools provides a tool named lm-profiler (laptop mode profiler)
1794 which handles block_dump on its own.
1796 See: $KERNEL-SOURCE/Documentation/laptop-mode.txt
1798 Also take a look at event-viewer(8) which is part of grml-debugtools.
1800 Install initrd via initramfs-tools for currently running kernel:
1802 # update-initramfs -c -t -k $(uname -r)
1804 Install initrd via yaird for currently running kernel:
1806 # yaird -o /boot/initrd.img-$(uname -r)
1808 Install initrd via yaird for specific kernel:
1812 # yaird -o /boot/initrd.img-2.6.15-1-686 2.6.15-1-686
1814 Reinstall package with its original configuration files:
1816 # apt-get install --reinstall -o DPkg::Options::=--force-confmiss -o \
1817 DPkg::Options::=--force-confnew package
1819 grml 0.8 funkenzutzler - rt2x00 drivers:
1821 To avoid conflicts with the other rt2x00-drivers the package rt2x00 (which
1822 includes beta-version drivers) is not installed by default. If you want to
1823 use the kernel modules rt2400pci, rt2500pci, rt2500usb, rt61pci and/or
1824 rt73usb please install the package manually running:
1826 # dpkg -i /usr/src/rt2x00-modules-*.deb
1828 Use Java with jikes and jamvm on grml:
1832 % cp /usr/share/doc/grml-templates/template.java .
1833 % jikes template.java
1836 Notice that grml exports $JIKESPATH (/usr/share/classpath/glibj.zip),
1837 so you do not have to manually run
1838 jikes --bootclasspath /usr/share/classpath/glibj.zip
1840 Online resizing of (Software-)RAID5:
1842 # Initiate a RAID5 setup for testing purposes:
1843 mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/hda1 /dev/hdb1 /dev/hdd1
1845 # Create filesystem, mount md0, create a testfile and save md5sum for
1848 mount /dev/md0 /mnt/test
1849 dd if=/dev/urandom of=/mnt/test/dd bs=512 count=10000
1850 md5sum /mnt/test/dd > md5sum
1852 # Make sure the RAID is synched via checking:
1855 # Now remove one partition:
1856 mdadm /dev/md0 --fail /dev/hdd1 --remove /dev/hdd1
1858 # Delete partition, create a new + bigger one and set partition type to fd
1859 # (Linux raid autodetect):
1862 # And re-add the partition:
1863 mdadm -a /dev/md0 /dev/hdd1
1865 # Make sure the RAID is synched via checking:
1868 # Repeat the steps for all other disks/partitions as well:
1869 mdadm /dev/md0 --fail /dev/hdb1 --remove /dev/hdb1
1871 mdadm -a /dev/md0 /dev/hdb1
1873 mdadm /dev/md0 --fail /dev/hda1 --remove /dev/hda1
1875 mdadm -a /dev/md0 /dev/hda1
1878 # Now resize the RAID5 system online [see 'man mdadm' for details]:
1879 mdadm --detail /dev/md0 | grep -e 'Array Size' -e 'Device Size'
1880 mdadm --grow /dev/md0 -z max
1881 mdadm --detail /dev/md0 | grep -e "Array Size" -e 'Device Size'
1883 # Last step - resize the filesystem (online again):
1886 ext3 online resizing:
1888 Starting with Linux kernel 2.6.10 you can resize ext3 online. With
1889 e2fsprogs >=1.39-1 new filesystems are created with directory indexing and
1890 on-line resizing enabled by default (see /etc/mke2fs.conf).
1894 cfdisk /dev/hda # create a partition with type 8e (lvm)
1895 pvcreate /dev/hda2 # create a physical volume
1896 vgcreate resize_me /dev/hda2 # create volume group
1897 lvcreate -n resize_me -L100 resize_me # create a logical volume
1898 mkfs.ext3 /dev/resize_me/resize_me # now create a new filesystem
1899 mount /dev/resize_me/resize_me /mnt/test # mount the new fs for demonstrating online resizing
1900 df -h # check the size of the partition
1901 lvextend -L+100M /dev/resize_me/resize_me # let's extend the logical volume
1902 resize2fs /dev/resize_me/resize_me # and finally resize the filesystem
1903 df -h # recheck the size of the partition
1905 This also works for Software-RAID. Demo:
1907 mdadm --create --verbose /dev/md0 --level=raid1 --raid-devices=2 /dev/hda2 /dev/hdb1
1909 mount /dev/md0 /mnt/test
1910 mdadm /dev/md0 --fail /dev/hda2 --remove /dev/hda2
1911 cfdisk /dev/hda # adjust partition size for hda2
1912 mdadm /dev/md0 --add /dev/hda2
1913 mdadm /dev/md0 --fail /dev/hdb1 --remove /dev/hdb1
1914 cfdisk /dev/hdb # adjust partition size for hdb1
1915 mdadm /dev/md0 --add /dev/hdb1
1916 mdadm --grow /dev/md0 --size=max
1919 Notice: online resizing works as soon as the kernel can re-read the
1920 partition table. So it works for example with LVM and SW-RAID but not with
1921 a plain device (/dev/[sh]d*). The kernel does not re-read the partition
1922 table if the device is already mounted.
1924 Use vim as an outline editor:
1926 % $PAGER /usr/share/doc/vim-vimoutliner/README.Debian
1930 Monitor directories/files for changes using iwatch
1932 Monitor /tmp for changes:
1935 Monitor files/directories specified in /etc/iwatch.xml
1936 and send mail on changes:
1939 Some often used mdadm commands:
1942 # mdadm --create --verbose /dev/md0 --level=raid1 --raid-devices=2 /dev/hda1 /dev/hdb1
1944 Display details of specific RAID:
1945 # mdadm --detail /dev/md0
1948 Simulating a drive failure by software:
1949 # mdadm --manage --set-faulty /dev/md0 /dev/hda1
1951 Remove disk from RAID:
1952 # mdadm /dev/md0 -r /dev/hda1
1954 Set disk as faulty and remove from RAID:
1955 # mdadm /dev/md0 --fail /dev/hda1 --remove /dev/hda1
1960 Restart a RAID-device:
1963 Add another disk to existing RAID setup (hotadd):
1964 # mdadm /dev/md0 -a /dev/hde1
1965 # mdadm --grow /dev/md0 --raid-devices=4
1967 Assemble and start all arrays:
1968 # mdadm --assemble --scan
1970 Assemble a specific array:
1971 # mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1 /dev/sdc1
1974 # mdadm --assemble --run --force --update=resync /dev/md0 /dev/sda1 /dev/sda2
1977 # mdadm --stop --scan
1979 Scan for and setup arrays automatically:
1980 # mdadm --assemble --scan --auto=yes --verbose
1982 Notice: If the above does not work make sure /etc/mdadm/mdadm.conf contains:
1984 CREATE owner=root group=disk mode=0660 auto=yes
1989 # /usr/share/mdadm/mkconf > /etc/mdadm/mdadm.conf
1992 Monitoring the sw raid
1993 # nohup mdadm --monitor --mail=root@localhost --delay=300 /dev/md0
1995 Producing /etc/mdadm/mdadm.conf:
1996 # mdadm --detail --scan > /etc/mdadm/mdadm.conf
1998 See also: man mdadm | less -p "^EXAMPLES"
1999 http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html
2001 A quick summary of the most commonly used RAID levels:
2004 => 2 disks each 160 GB: 320 GB data
2005 RAID 1: Mirrored Set
2006 => 2 disks each 160 GB: 160 GB data
2007 RAID 5: Striped Set with Parity
2008 => 3 disks each 160 GB: 320 GB data; 160 GB redundancy
2010 Common nested RAID levels:
2011 RAID 01: A mirror of stripes
2012 RAID 10: A stripe of mirrors
2013 RAID 30: A stripe across dedicated parity RAID systems
2014 RAID 100: A stripe of a stripe of mirrors
2016 -- http://en.wikipedia.org/wiki/RAID
2018 Logical Volume Management (LVM) with Linux
2023 | hda1 hdc1 (PV:s on partitions or whole disks)
2029 | usrlv rootlv varlv (LV:s)
2031 | ext3 ext3 xfs (filesystems)
2033 Often used commands:
2034 ~~~~~~~~~~~~~~~~~~~~
2036 Create a physical volume:
2037 # pvcreate /dev/hda2
2039 Create a volume group:
2040 # vgcreate testvg /dev/hda2
2042 Create a logical volume:
2043 # lvcreate -n test_lv -L100 testvg
2045 Resize a logical volume:
2046 # lvextend -L+100M /dev/resize_me/resize_me
2047 # resize2fs /dev/resize_me/resize_me # ext2/3
2048 # xfs_growfs /dev/resize_me/resize_me # xfs
2049 # resize_reiserfs -f /dev/resize_me/resize_me # reiserfs online
2050 # mount -o remount,resize /dev/resize_me/resize_me # jfs
2052 Create a snapshot of a logical volume:
2053 # lvcreate -L 500M --snapshot -n mysnap /dev/testvg/test_lv
2055 Deactivate a volume group:
2056 # vgchange -a n my_volume_group
2058 Actually remove a volume group:
2059 # vgremove my_volume_group
2061 Display information about physical volume:
2062 # pvdisplay /dev/hda1
2064 Remove physical volume:
2065 # vgreduce my_volume_group /dev/hda1
2067 Remove logical volume:
2068 # umount /dev/myvg/homevol
2069 # lvremove /dev/myvg/homevol
2072 http://www.tldp.org/HOWTO/LVM-HOWTO/
2074 How to use APT locally
2076 Sometimes you have lots of packages .deb that you would like to use APT to
2077 install so that the dependencies would be automatically solved. Solution:
2080 dpkg-scanpackages debs /dev/null | gzip > debs/Packages.gz
2081 echo " deb file:/root debs/" >> /etc/apt/sources.list
2082 dpkg-scansources debs | gzip > debs/Sources.gz
2083 echo " deb-src file:/root debs/" >> /etc/apt/sources.list
2085 See also: http://www.debian.org/doc/manuals/apt-howto/ch-basico.en.html
2087 Check filesystem's LABEL:
2090 # vol_id -l /dev/sda1
2092 ext2/3 without vol_id:
2093 # dumpe2fs /dev/sda1 | grep "Filesystem volume name"
2096 # xfs_admin -l /dev/sda1
2098 reiserfs without vol_id:
2099 # debugreiserfs /dev/sda1 | grep -i label
2102 # jfs_tune -l /dev/sda1 | grep -i label
2104 reiser4 without vol_id:
2105 # debugfs.reiser4 /dev/sda1 | grep -i label
2107 Check filesystem's UUID:
2110 # vol_id -u /dev/sda1
2112 ext2/3 without vol_id:
2113 # dumpe2fs /dev/sda1 | grep -i UUID
2116 # xfs_admin -u /dev/sda1
2118 reiserfs without vol_id:
2119 # debugreiserfs /dev/sda1 | grep -i UUID
2121 reiser4 without vol_id:
2122 # debugfs.reiser4 /dev/sda1 | grep -i UUID
2124 Change a filesystem's LABEL:
2127 # mkswap -L $LABEL /dev/sda1
2130 # e2label /dev/sda1 $LABEL
2131 # tune2fs -L $LABEL /dev/sda1
2134 # reiserfstune -l $LABEL /dev/sda1
2137 # jfs_tune -L $LABEL /dev/sda1
2140 # xfs_admin -L $LABEL /dev/sda1
2143 # echo 'drive i: file="/dev/sda1"' >> ~/.mtoolsrc
2144 # mlabel -s i:$LABEL
2147 # ntfslabel $LABEL /dev/sda1
2149 Disable pdiffs feature of APT:
2152 # echo 'Acquire::PDiffs "false";' >> /etc/apt/apt.conf
2155 # apt-get update -o Acquire::Pdiffs=false
2157 Backup big devices or files and create compressed splitted
2158 image chunks of it using zsplit
2160 Create backup of /dev/sda named archiveofsda_#.spl.zp in directory
2161 /mnt/sda1/backup, split the files up into chunks of 1GB each and set
2162 read/write buffer to 256kB:
2163 # zsplit -b 256 -N archiveofsda -o /mnt/sda1/backup/ -s 1G /dev/sda
2165 Restore the backup using unzsplit:
2166 # unzsplit -D /dev/sda -d archiveofsda
2168 More usage examples: man zsplit + man unzsplit
2170 Measure network performance using iperf:
2176 % iperf -c <server_address> -V
2180 Server with 128k TCP window size:
2183 Client with running for 60 seconds and bidirectional test:
2184 % iperf -c <server_address> -r -w128k -t60
2186 Framebuffer resolutions:
2188 Resolution in pixels
2189 Color depth | 640x480 800x600 1024x768 1280x1024
2190 256 (8bit)| 769 771 773 775
2191 32000 (15bit)| 784 787 790 793
2192 65000 (16bit)| 785 788 791 794
2193 16.7 Mill.(24bit)| 786 789 792 795
2197 Mode 0x0300: 640x400 (+640), 8 bits
2198 Mode 0x0301: 640x480 (+640), 8 bits
2199 Mode 0x0303: 800x600 (+800), 8 bits
2200 Mode 0x0303: 800x600 (+832), 8 bits
2201 Mode 0x0305: 1024x768 (+1024), 8 bits
2202 Mode 0x0307: 1280x1024 (+1280), 8 bits
2203 Mode 0x030e: 320x200 (+640), 16 bits
2204 Mode 0x030f: 320x200 (+1280), 24 bits
2205 Mode 0x0311: 640x480 (+1280), 16 bits
2206 Mode 0x0312: 640x480 (+2560), 24 bits
2207 Mode 0x0314: 800x600 (+1600), 16 bits
2208 Mode 0x0315: 800x600 (+3200), 24 bits
2209 Mode 0x0317: 1024x768 (+2048), 16 bits
2210 Mode 0x0318: 1024x768 (+4096), 24 bits
2211 Mode 0x031a: 1280x1024 (+2560), 16 bits
2212 Mode 0x031b: 1280x1024 (+5120), 24 bits
2213 Mode 0x0330: 320x200 (+320), 8 bits
2214 Mode 0x0331: 320x400 (+320), 8 bits
2215 Mode 0x0332: 320x400 (+640), 16 bits
2216 Mode 0x0333: 320x400 (+1280), 24 bits
2217 Mode 0x0334: 320x240 (+320), 8 bits
2218 Mode 0x0335: 320x240 (+640), 16 bits
2219 Mode 0x0336: 320x240 (+1280), 24 bits
2220 Mode 0x033c: 1400x1050 (+1408), 8 bits
2221 Mode 0x033d: 640x400 (+1280), 16 bits
2222 Mode 0x033e: 640x400 (+2560), 24 bits
2223 Mode 0x0345: 1600x1200 (+1600), 8 bits
2224 Mode 0x0346: 1600x1200 (+3200), 16 bits
2225 Mode 0x034d: 1400x1050 (+2816), 16 bits
2226 Mode 0x035c: 1400x1050 (+5632), 24 bits
2228 Portscan using netcat:
2230 # netcat -v -w2 <host|ip-addr.> 1-1024
2232 Run apt-get but disable apt-listchanges:
2234 APT_LISTCHANGES_FRONTEND=none apt-get ...
2236 Upgrade system but disable apt-listbugs:
2238 APT_LISTBUGS_FRONTEND=none apt-get ...
2240 Set up a Transparent Debian Proxy
2242 Install of apt-cacher, the default config will do:
2243 # apt-get install apt-cacher
2245 Check out the ip address of debian mirror(s).
2246 Then add this to your firewall script:
2248 DEBIAN_MIRRORS="141.76.2.4 213.129.232.18"
2249 for ip in ${DEBIAN_MIRRORS} ; do
2250 ${IPTABLES} -t nat -A PREROUTING -s $subnet -d $ip -p tcp --dport 80 -j REDIRECT --to-port 3142
2253 where ${IPTABLES} is the location of your iptables binary
2254 and $subnet is your internal subnet.
2256 Now everybody in your subnet who does access either
2257 ftp.de.debian.org or ftp.at.debian.org will actually
2258 access your apt-cacher instead.
2260 To use apt-cacher on the router itself, add the following
2261 line to your /etc/apt/apt.conf:
2263 Acquire::http::Proxy "http://localhost:3142/";
2265 Version control using Mercurial
2267 Setting up a Mercurial project:
2270 % hg init # creates .hg
2271 % hg add # add all files
2272 % hg commit # commit all changes, edit changelog entry
2274 Branching and merging:
2276 % hg clone linux linux-work # create a new branch
2281 % hg pull ../linux-work # pull changesets from linux-work
2282 % hg merge # merge the new tip from linux-work into
2283 # (old versions used "hg update -m" instead)
2284 # our working directory
2285 % hg commit # commit the result of the merge
2289 % cat ../p/patchlist | xargs hg import -p1 -b ../p
2297 % hg export 1234 > foo.patch # export changeset 1234
2299 Export your current repo via HTTP with browsable interface:
2301 % hg serve -n "My repo" -p 80
2303 Pushing changes to a remote repo with SSH:
2305 % hg push ssh://user@example.com/~/hg/
2307 Merge changes from a remote machine:
2309 host1% hg pull http://foo/
2310 host2% hg merge # merge changes into your working directory
2312 Set up a CGI server on your webserver:
2313 % cp hgwebdir.cgi ~/public_html/hg/index.cgi
2314 % $EDITOR ~/public_html/hg/index.cgi # adjust the defaults
2316 Mercurial repositories of grml can be found at http://hg.grml.org/
2318 Download binary codecs for mplayer:
2320 # /usr/share/mplayer/scripts/win32codecs.sh
2324 # /usr/share/mplayer/scripts/binary_codecs.sh install
2326 (depending on the mplayer version you have).
2328 To play encrypted DVDs and if you are living in a country where using
2329 libdvdcss code is not illegal can install Debian package libdvdread3
2330 and use the script /usr/share/doc/libdvdread3/install-css.sh.
2332 Read manpages of uninstalled packages with debman:
2334 % debman -p git-core git
2336 Test network performance using netperf:
2342 # netperf -t TCP_STREAM -H 192.168.0.41
2344 Setup Xen within 20 minutes on Debian/grml
2346 Install relevant software und update grub's menu.lst (Xen does not work with
2347 usual lilo so install grub instead if not done already):
2349 apt-get install linux-image-2.6.18-1-xen-686 xen-hypervisor-3.0.3-1-i386 \
2350 xen-utils-3.0.3-1 xen-tools bridge-utils
2353 Example for installation of Debian etch as DomU:
2356 xen-create-image --debootstrap --dir=/mnt/md1/xen --size=2Gb --memory=512Mb --fs=ext3 \
2357 --cache=yes --dist=etch --hostname=xengrml1 --ip 192.168.1.2 --netmask 255.255.255.0 \
2358 --gateway 192.168.1.1 --initrd=/boot/initrd.img-2.6.18-1-xen-686 \
2359 --kernel=/boot/vmlinuz-2.6.18-1-xen-686 --mirror=http://ftp.at.debian.org/debian/
2363 /etc/init.d/xend start
2364 /etc/init.d/xendomains start
2366 Setup a bridge for network, either manually:
2368 brctl addbr xenintbr
2369 brctl stp xenintbr off
2370 brctl sethello xenintbr 0
2371 brctl setfd xenintbr 0
2372 ifconfig xenintbr 192.168.1.1 netmask 255.255.255.0 up
2374 or via /etc/network/interfaces (run ifup xenintbr to bring up the device then
2378 iface xenintbr inet static
2379 pre-up brctl addbr xenintbr
2380 post-down brctl delbr xenintbr
2382 netmask 255.255.255.0
2387 Setup forwarding (adjust $PUBLIC_IP; for permanet setup use /etc/sysctl.conf and
2388 add the iptables commands to a startup script like /etc/init.d/rc.local):
2390 echo 1 > /proc/sys/net/ipv4/ip_forward
2391 iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j SNAT --to $PUBLIC_IP
2392 iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to $PUBLIC_IP
2394 Adjust network configuration of Xend:
2396 cat >> /etc/xen/xend-config.sxp << EOF
2397 (network-script network-route)
2398 (vif-bridge xenintbr)
2399 (vif-script vif-bridge)
2402 List domains, start up a DomU, shutdown later again:
2404 xm create -c /etc/xen/xengrml1.cfg
2408 This HowTo is also available online at http://grml.org/xen/
2410 Play tetris with zsh:
2414 bindkey "^Xt" tetris
2416 Now press 'ctrl-x t'.
2418 Set up a router with grml
2420 Run grml-router script:
2423 Install dnsmasq if not already present:
2424 # apt-get update ; apt-get install dnsmasq
2426 Adjust /etc/dnsmasq.conf according to your needs:
2427 # cat >> /etc/dnsmasq.conf << EOF
2430 dhcp-range=19.168.0.124,192.168.0.254,1m # dhcp range
2431 dhcp-option=3,192.168.0.1 # dns server
2432 dhcp-option=1,255.255.255.0 # netmask
2435 Start dnsmasq finally:
2438 Display stats about memory allocations performed by a program:
2440 Usage example for 'ls':
2442 % LD_PRELOAD=/lib/libmemusage.so ls > /dev/null
2444 Use KVM (Kernel-based Virtual Machine for Linux):
2446 Make sure to install the relevant tools:
2447 # apt-get update ; apt-get install kvm
2450 Test it with a minimal system like ttylinux:
2451 # wget http://www.minimalinux.org/ttylinux/packages/bootcd-i386-5.3.iso.gz
2452 # gzip -d bootcd-i386-5.3.iso.gz
2453 # kvm -cdrom bootcd-i386-5.3.iso
2455 EEPROM data decoding for SDRAM DIMM modules:
2458 # /usr/share/doc/lm-sensors/examples/eeprom/decode-dimms.pl
2462 Make sure your device is supported by Linux and running.
2463 See http://www.linuxtv.org/ for more details.
2465 If the DVB device works on your system (see 'hwinfo --usb'
2466 when using a DVB usb device for example), then make sure you
2467 have the scan util from dvb-utils available:
2469 # aptitude install dvb-utils
2471 Then create a channels.conf configuration file:
2473 % scan /usr/share/doc/dvb-utils/examples/scan/... > ~/.mplayer/channels.conf
2475 You can find some example configuration files on
2476 your grml system in ~/.channels. Usage example:
2478 % ln -s ~/.mplayer/channels.conf-AT-graz ~/.mplayer/channels.conf
2480 Tip: w_scan (see http://free.pages.at/wirbel4vdr/w_scan/index2.html)
2481 might be useful if you do not know the initial configuration
2484 Get the lastest mercurial snapshot:
2486 Make sure you have the python-dev package available:
2487 # apt-get update ; apt-get install python-dev
2489 Get and build the source:
2490 % hg clone http://selenic.com/repo/hg mercurial
2493 % export PYTHONPATH=$(pwd)
2494 % export PATH=$PATH:$(pwd)
2496 now you should have the newest version of mercurial whenever you execute hg.
2498 To update to the lastest development snapshot, additionally use
2499 the following commands:
2500 % hg pull -u http://hg.intevation.org/mercurial/crew
2506 Available bootoptions relevant in live-cd mode:
2507 -----------------------------------------------
2509 * utc: set UTC, if your system clock is set to UTC (GMT)
2510 * gmt: set UTC, if your system clock is set to UTC (GMT) [like bootoption utc]
2511 * tz=$option: set timezone to corresponding $option, usage example:
2514 Configuration options relevant on harddisk installation:
2515 --------------------------------------------------------
2517 * Use the tzconfig utility to set the local timezone:
2521 which adjusts /etc/timezone and /etc/localtime according
2522 to the provided information. Running:
2524 # dpkg-reconfigure tzdata
2526 might be useful as well.
2528 * /etc/default/rcS: set variable UTC according to your needs,
2529 whether your system clock is set to UTC (UTC='yes') or
2532 * /etc/localtime: adjust zoneinfo according to your needs:
2534 # ln -sf /usr/share/zoneinfo/$WHATEVER_YOU_WANT /etc/localtime
2536 The zoneinfo directory contains the time zone files that were
2537 compiled by zic. The files contain information such as rules
2538 about DST. They allow the kernel to convert UTC UNIX time into
2539 appropriate local dates and times. Use the zdump utility to
2540 print current time and date (in the specified time zone).
2542 * /etc/adjtime: This file is used e.g. by the adjtimex function,
2543 which can smoothly adjust system time while the system runs
2545 * If you change the time (using 'date --set ...', ntpdate,...)
2546 it is worth setting also the hardware clock to the correct time:
2548 # hwclock --systohc [--utc]
2550 Remember to add the --utc -option if the hardware clock is set
2556 Check your current settings via:
2559 zdump /etc/localtime
2562 grep hwclock /etc/runlevel.conf
2563 grep '^UTC' /etc/default/rc
2565 Further information:
2566 --------------------
2568 hwclock(8) tzselect(1) tzconfig(8)
2569 http://www.debian.org/doc/manuals/system-administrator/ch-sysadmin-time.html
2570 http://wiki.debian.org/TimeZoneChanges
2572 Recorder shellscript session using script:
2574 % script -t 2>~/upgrade.time -a ~/upgrade.script
2575 % scriptreplay ~/upgrade.time ~/upgrade.script
2577 Test UTF-8 capabilities of terminal:
2579 wget http://melkor.dnp.fmph.uniba.sk/~garabik/debian-utf8/download/UTF-8-demo.txt.gz
2580 zcat UTF-8-demo.txt.gz
2584 wget http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt
2587 UTF-8 at grml / some general information regarding Unicde/UTF-8:
2589 http://wiki.grml.org/doku.php?id=utf8
2592 This allows one ssh connection attepmt per minute per source ip, with a initial
2593 burst of 10. The available burst is like a counter which is initialised with
2594 10. Every connection attempt decrements the counter, and every minute where the
2595 connection limit of one per minute is not overstepped the counter is
2596 incremented by one. If the burst counter is exhausted the real rate limit
2597 comes into play. This gives you 11 connectionattepmts in the first minute
2598 before blocked for 10minutes. After 10 minutes block the game restarts.
2600 Hint: you could set the burst value to 5 and the block time to only 5 minutes
2601 to achive the same average connection rate but with halve the block time.
2603 iptables -A inet_in -p tcp --syn --dport 22 -m hashlimit --hashlimit-name ssh \
2604 --hashlimit 1/minute \ --hashlimit-burst 10 --hashlimit-mode srcip \
2605 --hashlimit-htable-expire 600000 -j ACCEPT
2606 iptables -A inet_in -p tcp --dport 22 -m state --state NEW -j REJECT
2608 Tunnel a specific connection via socat:
2611 % socat TCP4-LISTEN:8003 TCP4:gateway:500
2614 # socat TCP4-LISTEN:500,fork TCP4:target:$PORT
2616 Using localhost:8003 on the client uses the tunnel now.
2620 # date --set=060916102007
2622 where the bits are month(2)/day(2)/hour(2)/minute(2)/year(4)
2624 Set date using a relative date:
2630 # date -s '+tomorrow'
2632 Display a specific relative date:
2634 # date -d '+5 days -2 hours'
2636 Don't forget to set hardware clock via:
2640 Booting grml via network / PXE:
2642 Start grml-terminalserver on a system with network access
2643 and where grml is running:
2645 # grml-terminalserver
2647 Then booting your client(s) via PXE should work without
2650 See: man grml-terminalserver + http://grml.org/terminalserver/
2652 Debugging SSL communications:
2654 % openssl s_client -connect server.adress:993
2658 # ssldump -a -A -H -i eth0
2660 See http://prefetch.net/articles/debuggingssl.html for more details.
2662 Remove bootmanager from MBR:
2664 # lilo -M /dev/hda -s /dev/null
2666 Rewrite grub to MBR:
2669 # grub-install --recheck --no-floppy --root-directory=/mnt/sda1 /dev/sda
2671 Rewrite lilo to MBR:
2676 Create screenshot of plain/real console - tty1:
2678 # fbgrab -c 1 screeni.png
2680 Create screenshot when running X:
2684 Tip: use the gkrellshoot plugin when using gkrellm
2686 Redirect all connections to hostA:portA to hostB:portB, where hostA and hostB are
2689 Run the following commands on hostA:
2691 echo 1 > /proc/sys/net/ipv4/ip_forward
2692 iptables -t nat -A PREROUTING -p tcp --dport portA -j DNAT --to hostB:portB
2693 iptables -A FORWARD -i eth0 -o eth0 -d hostB -p tcp --dport portB -j ACCEPT
2694 iptables -A FORWARD -i eth0 -o eth0 -s hostB -p tcp --sport portB -j ACCEPT
2695 iptables -t nat -A POSTROUTING -p tcp -d hostB --dport portB -j SNAT --to-source hostA
2697 Flash BIOS without DOS/Windows:
2699 Dump flash info and set the flash chip to writable:
2702 Backup the original BIOS:
2703 # flashrom -r backup.bin
2705 Notice: the following step will overwrite your current BIOS!
2706 So make sure you really know what you are doing.
2708 Flash the BIOS image:
2709 # flashrom -wv newbios.bin
2711 Also check out LinuxBIOS: http://linuxbios.org/
2713 Enable shadow passwords:
2717 Set up an IPv6 tunneln on grml:
2721 Set up console newsreader slrn for use with Usenet:
2725 Calculate with IPv6 addresses:
2729 For usage examples refer to manpage ipv6calc(8).
2731 Common network debugging tools for use with IPv6:
2740 Set up NFS (Network File System):
2744 Make sure the relevant services are running on the server side:
2746 # /etc/init.d/portmap start
2747 # /etc/init.d/nfs-common start
2748 # /etc/init.d/nfs-kernel-server start
2750 Export shares via /etc/exports:
2752 /backups 192.168.1.100/24(rw,wdelay,no_root_squash,async,subtree_check)
2754 ... or manually export a directory running:
2756 # exportfs -o rw,wdelay,no_root_squash,async,subtree_check 192.168.1.100:/backups
2758 and unexport a share running:
2760 # exportfs -u 192.168.1.100:/backups
2762 and every time when you modify /etc/exports file run
2766 Display what NFS components are running:
2770 Display list of exported shares:
2778 Make sure the relevant services are running on the client side:
2780 # /etc/init.d/portmap start
2781 # /etc/init.d/nfs-common start
2783 Verify that the server allows you to access its RPC/NFS services:
2785 # rpcinfo -p server_name
2787 Check what directories the server exports:
2789 # showmount -e server_name
2791 On the client side you can use something like the following in /etc/fstab:
2793 192.168.1.101:/backups /mnt/nfs nfs defaults,users,wsize=8192,rsize=8192 0 0
2797 # aptitude install cloop-src
2800 # modprobe cloop file=/path/to/cloop/file
2801 # mount -r -t iso9660 /dev/cloop /mnt/test
2803 Create a PS/PDF of a plaintext file:
2805 % a2ps --medium A4dj -E -o output.ps input_file
2808 Print two pages on one in a PDF file:
2810 % pdfnup --nup 2x1 input.pdf
2812 Concatenate, extract pages/parts, encrypt/decrypt,
2813 compress PDFs using 'pdftk'.
2815 Read a PS/PDF file on console:
2819 or on plain framebuffer console in graphical mode:
2821 % pdf2ps file.pdf ; ps2png file.ps file.png ; fbi file.png
2827 Bypass the password of a PDF file:
2829 % gs -q -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=output.pdf input.pdf -c quit
2835 This will record a AIFF audio file.
2837 Change passphrase / password of an existing SSH key:
2841 Enable syntax highlighting in nano:
2843 Just uncomment the include directives for your respective
2844 language at the bottom of the file /etc/nanorc
2846 Create netboot package for grml-terminalserver:
2848 # sh /usr/share/doc/grml-terminalserver/examples/create-netboot
2850 To boot grml via network (PXE) check out grml-terminalserver:
2852 # grml-terminalserver
2854 See http://grml.org/terminalserver/ for more details.
2858 Using the 'Orientation' tag of the Exif header, rotate
2859 the image so that it is upright:
2860 % jhead -autorot *.jpg
2862 Manually rotate a picture:
2863 % convert -rotate 270 input.jpg output.jpg
2865 Rename files based on the information inside their exif header:
2867 % jhead -n%Y-%m-%d_%Hh%M_%f *.jpg
2869 This will rename a file named img_2071.jpg to something like:
2871 2007-08-17_10h38_img_2071.jpg
2873 if it was shot at 10:38 o'clock on 2007-08-17 (according to
2874 the information inside the exif header).
2876 Calculate network / netmask:
2879 % ipcalc 10.0.0.28 255.255.255.0
2880 % ipcalc 10.0.0.0/24
2882 Blacklist a kernel module:
2884 # blacklist <name_of_kernel_module>
2886 -> running 'blacklist hostap_cs' for example will generate an
2887 entry like this in /etc/modprobe.d/grml:
2892 To remove the module from the blacklist again just invoke:
2894 # unblacklist <name_of_kernel_module>
2896 or manually remove the entry from /etc/modprobe.d/grml.
2898 Create a Debian package of a perl module:
2900 % dh-make-perl --cpan Acme::Smirch --build
2902 The Magic SysRq Keys (SysReq or Sys Req, short for System Request):
2904 To reboot your system using the SysRq keys just hold down the Alt and
2905 SysRq (Print Screen) key while pressing the keys REISUB ("Raising
2906 Elephants Is So Utterly Boring").
2908 R = take the keyboard out of raw mode
2909 E = terminates all processes (except init)
2910 I = kills all processes (except init)
2911 S = synchronizes the disk(s)
2912 U = remounts all filesystems read-only
2913 B = reboot the system
2915 Notice: use O instead of B for poweroff.
2917 Or write the sequence to /proc/sysrq-trigger instead:
2919 # for i in r e i s u b ; do echo $i > /proc/sysrq-trigger ; done
2921 To enable or disable SysRq calls:
2923 # echo 0 > /proc/sys/kernel/sysrq
2924 # echo 1 > /proc/sys/kernel/sysrq
2926 See http://en.wikipedia.org/wiki/Magic_SysRq_key for more details.
2930 Just boot your grml Live-CD with "memtest" to execute a memcheck/memtest
2933 Tunnel TCP-Traffic through DNS using dns2tcp:
2937 1. Create necessary DNS-Records:
2938 dnstun.example.com. 3600 IN NS host.example.com.
2939 dnstun.example.com. 3600 IN A 192.168.1.1
2940 host.example.com. 3600 IN A 192.168.1.1
2942 2. Configure dns2tcpd on host.example.com.:
2943 # cat /etc/dns2tcpd.conf
2944 listen = 192.168.1.1 #the ip dnstun should listen on
2945 port = 53 #" port " " " "
2948 domain = dnstun.example.com. # the zone as specified inside dns
2949 ressources = ssh:127.0.0.1:22 # available resources
2951 3. Start the daemon:
2952 # cat > /etc/default/dns2tcp << EOF
2953 # Set ENABLED to 1 if you want the init script to start dns2tcpd.
2957 # /etc/init.d/dns2tcp start
2961 You have two possibilities:
2962 - Use the DNS inside your network (DNS must allow resolving for external domains)
2963 # grep nameserver /etc/resolv.conf
2964 nameserver 172.16.42.1
2965 # dns2tcpc -z dnstun.example.com 172.16.42.1
2966 Available connection(s) :
2968 # dns2tcpc -r ssh -l 2222 -z dnstun.example.com 172.16.42.1 &
2969 Listening on port : 2222
2970 # ssh localhost -p 2222
2971 user@host.example.com:~#
2973 - Directly contact the endpoint (port 53 UDP must be allowed outgoing)
2974 # dns2tcpc -z dnstun.example.com dnstun.example.com
2975 Available connection(s) :
2977 # dns2tcpc -r ssh -l 2222 -z dnstun.example.com dnstun.example.com &
2978 Listenning on port : 2222
2979 # ssh localhost -p 2222
2980 user@host.example.com:~#
2982 Notice: using 'ssh -D 8080 ..' you will get a socks5-proxy listening on
2983 localhost:8080 which you can use to tunnel everything through your "dns-uplink".
2985 Configure a MadWifi device for adhoc mode:
2987 Disable the autocreation of athX devices:
2988 # echo "options ath_pci autocreate=none" > /etc/modprobe.d/madwifi
2990 Remove the autocreated device for now:
2991 # wlanconfig ath0 destroy
2993 Configuration in /etc/network/interfaces:
2995 iface ath0 inet static
3001 - Do not use interface names without ending 0 (otherwise startup fails).
3002 - Only chooss unique names for interfaces.