X-Git-Url: http://git.grml.org/?a=blobdiff_plain;f=grml_tips;h=66f46a541a30d81d6dc2e36d540779e78c06ad58;hb=42d529ed4951169521e868ba6bd35abc70de8c1a;hp=e044aaf781c2d68d662a33aaa07ee45b993a6da7;hpb=90c21e0b0520af0cfe60c804f6a8e1390604b93d;p=grml-tips.git diff --git a/grml_tips b/grml_tips index e044aaf..66f46a5 100644 --- a/grml_tips +++ b/grml_tips @@ -43,12 +43,6 @@ Configure network: # grml-network -- -Boot grml via network: - -# grml-terminalserver - -See: man grml-terminalserver + http://grml.org/terminalserver/ --- Deactivate error correction of zsh: % NOCOR=1 zsh @@ -413,13 +407,17 @@ Test sound: Improved grep version: % glark +-- +Grep with highlighting: -glark grep extract-matches +% grep --color=auto ... +% hgrep ... -- -Highlith +Extract matches when grepping: -grepc -hgrep +Usage examples: +% ifconfig | grepc 'inet addr:(.*?)\s' +% ifconfig | glark --extract-matches 'inet addr:(.*?)\s' -- Output text as sound: @@ -580,6 +578,10 @@ Save live audio stream to file: or % mencoder mms://file.wmv -o $FILE -ovc copy -oac copy + +or + +% mimms mms://file.wmv -- Merge video files: @@ -655,7 +657,9 @@ to get a list of all supported trees -- Transfer your SSH public key to another host: -% ssh-copy-id -i ~/.ssh/id_dsa.pub user@remote-system +% ssh-keygen # ssh-keygen / ssh-key-gen: if you don't have a key yet +[...] +% ssh-copy-id -i ~/.ssh/id_rsa.pub user@remote-system or % cat $HOME/.ssh/id_rsa.pub | ssh user@remote-system 'cat >> .ssh/authorized_keys' -- @@ -700,9 +704,9 @@ Write back the guessed table: Develop, test and use exploit code with the Metasploit Framework: cd /tmp -wget http://www.metasploit.com/tools/framework-2.7-snapshot.tar.gz -unp framework-2.7-snapshot.tar.gz -cd framework* +wget http://framework-mirrors.metasploit.com/msf/downloader/framework-3.0.tar.gz +unp framework-3.0.tar.gz +cd framework-3.0 ./msfcli -- Useful documentation: @@ -1084,9 +1088,9 @@ EOF See also: http://www.debian.org/releases/stable/i386/apcs04.html.en Avoid all of the above steps - use grml-debootstrap(8) instead! -- -Convert files from Unicode / UTF to ISO: +Convert files from Unicode / UTF-8 to ISO: -% iconv -f utf8 -t iso-8859-15 < utffile > isofile +% iconv -c -f utf8 -t iso-8859-15 < utffile > isofile and vice versa: @@ -1270,8 +1274,7 @@ Write a Windows 2000/XP/2003 MBR to device: Use a Vodafone 3G Datacard (UMTS) with Linux: Plug in your vodafone card and check in syslog whether the appropriate -(probably /dev/ttyUSB0 or /dev/noz0 when using newer vodafone cards) has -been created. If so run: +(probably /dev/ttyUSB0 or /dev/noz0) has been created. If so run: # gcom -d $DEVICE # wvdial --config /etc/wvdial.conf.umts $PROFILE @@ -1286,8 +1289,28 @@ Usage examples: # gcom -d /dev/noz0 # wvdial --config /etc/wvdial.conf.umts dreiusb -Notice: newer vodafone cards require the nozomi driver. Run 'modprobe nozomi' on -your grml system. +If you receive invalid DNS nameservers when connecting, like: + +[...] +--> primary DNS address 10.11.12.13 +--> secondary DNS address 10.11.12.14 + +just provide a working nameserver to resolvconf via: + +# echo "nameserver 80.120.17.70" | resolvconf -a ppp0 + +Notice: some vodafone cards require the nozomi driver (run 'modprobe nozomi' on +your grml system), some other ones require the sierra driver (run +'modprobe sierra'). + +If your device isn't supported by usbserial yet, manually provide vendor and +product ID when loading the usbserial module. Usage example: + +% lsusb +[...] +Bus 004 Device 008: ID 1199:6813 Sierra Wireless, Inc. + +# modprobe usbserial vendor=0x1199 product=0x6813 -- hdparm - get/set hard disk parameters @@ -1711,7 +1734,7 @@ GET http://www.google.com HTTP/1.0 [press enter twice] Adjust system for use of qemu with kqemu: Make sure you have all you need: -# apt-get update ; apt-get install qemu grml-kerneladdons-$KERNELVERSION +# aptitude update ; aptitude install qemu kqemu-modules-$(uname -r) Then set up kqemu: @@ -1752,12 +1775,16 @@ Start X and lock console via exiting: % startx 2>~/.xsession-errors &| exit -- -Which process is writing to disk? +Which process is writing to disk and/or causes the disk to spin up? + +First of all use lsof to check what's going on. Does not help? -> # echo 1 > /proc/sys/vm/block_dump -Warning: you must disable syslogd before you do this, or you must -make sure that kernel output is not logged. +The command sets a sysctl to cause the kernel to log all disk +writes. Please notice that there is a lot of data. So please +disable syslogd/syslog-ng before you do this, or you must make +sure that kernel output is not logged. When you're done, disable block dump using: # echo 0 > /proc/sys/vm/block_dump @@ -1765,6 +1792,10 @@ When you're done, disable block dump using: Alternative: laptop-mode-tools provides a tool named lm-profiler (laptop mode profiler) which handles block_dump on its own. + +See: $KERNEL-SOURCE/Documentation/laptop-mode.txt + +Also take a look at event-viewer(8) which is part of grml-debugtools. -- Install initrd via initramfs-tools for currently running kernel: @@ -2065,10 +2096,13 @@ xfs without vol_id: # xfs_admin -l /dev/sda1 reiserfs without vol_id: -# debugreiserfs /dev/sda1 | grep UUID +# debugreiserfs /dev/sda1 | grep -i label + +jfs without vol_id: +# jfs_tune -l /dev/sda1 | grep -i label reiser4 without vol_id: -# debugfs.reiser4 /dev/sda1 | grep uuid +# debugfs.reiser4 /dev/sda1 | grep -i label -- Check filesystem's UUID: @@ -2076,16 +2110,41 @@ generic way: # vol_id -u /dev/sda1 ext2/3 without vol_id: -# dumpe2fs /dev/sda1 | grep UUID +# dumpe2fs /dev/sda1 | grep -i UUID xfs without vol_id: # xfs_admin -u /dev/sda1 reiserfs without vol_id: -# debugreiserfs /dev/sda1 | grep LABEL +# debugreiserfs /dev/sda1 | grep -i UUID reiser4 without vol_id: -# debugfs.reiser4 /dev/sda1 | grep label +# debugfs.reiser4 /dev/sda1 | grep -i UUID +-- +Change a filesystem's LABEL: + +swap: +# mkswap -L $LABEL /dev/sda1 + +ext2/ext3: +# e2label /dev/sda1 $LABEL +# tune2fs -L $LABEL /dev/sda1 + +reiserfs: +# reiserfstune -l $LABEL /dev/sda1 + +jfs: +# jfs_tune -L $LABEL /dev/sda1 + +xfs: +# xfs_admin -L $LABEL /dev/sda1 + +fat/vfat: +# echo 'drive i: file="/dev/sda1"' >> ~/.mtoolsrc +# mlabel -s i:$LABEL + +ntfs: +# ntfslabel $LABEL /dev/sda1 -- Disable pdiffs feature of APT: @@ -2108,7 +2167,7 @@ Restore the backup using unzsplit: More usage examples: man zsplit + man unzsplit -- -Measure network performance using ipserf +Measure network performance using iperf: Server side: % iperf -s -V @@ -2260,6 +2319,12 @@ Download binary codecs for mplayer: # /usr/share/mplayer/scripts/win32codecs.sh +or + +# /usr/share/mplayer/scripts/binary_codecs.sh install + +(depending on the mplayer version you have). + To play encrypted DVDs and if you are living in a country where using libdvdcss code is not illegal can install Debian package libdvdread3 and use the script /usr/share/doc/libdvdread3/install-css.sh. @@ -2370,17 +2435,6 @@ EOF Start dnsmasq finally: # Restart dnsmasq -- -Find out which process(es) cause the disk to spin up: - -# echo 1 > /proc/sys/vm/block_dump - -The command sets a sysctl to cause the kernel to log all disk -writes. Please notice that there is a lot of data. - -See: $KERNEL-SOURCE/Documentation/laptop-mode.txt - -Also take a look at event-viewer(8). --- Display stats about memory allocations performed by a program: Usage example for 'ls': @@ -2398,3 +2452,553 @@ Test it with a minimal system like ttylinux: # gzip -d bootcd-i386-5.3.iso.gz # kvm -cdrom bootcd-i386-5.3.iso -- +EEPROM data decoding for SDRAM DIMM modules: + +# modprobe eeprom +# /usr/share/doc/lm-sensors/examples/eeprom/decode-dimms.pl +-- +Set up and use DVB: + +Make sure your device is supported by Linux and running. +See http://www.linuxtv.org/ for more details. + +If the DVB device works on your system (see 'hwinfo --usb' +when using a DVB usb device for example), then make sure you +have the scan util from dvb-utils available: + +# aptitude install dvb-utils + +Then create a channels.conf configuration file: + +% scan /usr/share/doc/dvb-utils/examples/scan/... > ~/.mplayer/channels.conf + +You can find some example configuration files on +your grml system in ~/.channels. Usage example: + +% ln -s ~/.mplayer/channels.conf-AT-graz ~/.mplayer/channels.conf + +Tip: w_scan (see http://free.pages.at/wirbel4vdr/w_scan/index2.html) +might be useful if you do not know the initial configuration +details. +-- +Get the lastest mercurial snapshot: + +Make sure you have the python-dev package available: +# apt-get update ; apt-get install python-dev + +Get and build the source: +% hg clone http://selenic.com/repo/hg mercurial +% cd mercurial +% make local +% export PYTHONPATH=$(pwd) +% export PATH=$PATH:$(pwd) + +now you should have the newest version of mercurial whenever you execute hg. + +To update to the lastest development snapshot, additionally use +the following commands: +% hg pull -u http://hg.intevation.org/mercurial/crew +% make local +-- +Configure timezone +================== + +Available bootoptions relevant in live-cd mode: +----------------------------------------------- + +* utc: set UTC, if your system clock is set to UTC (GMT) +* gmt: set UTC, if your system clock is set to UTC (GMT) [like bootoption utc] +* tz=$option: set timezone to corresponding $option, usage example: + tz=Europe/Vienna + +Configuration options relevant on harddisk installation: +-------------------------------------------------------- + +* Use the tzconfig utility to set the local timezone: + + # tzconfig + + which adjusts /etc/timezone and /etc/localtime according + to the provided information. Running: + + # dpkg-reconfigure tzdata + + might be useful as well. + +* /etc/default/rcS: set variable UTC according to your needs, + whether your system clock is set to UTC (UTC='yes') or + not (UTC='no') + +* /etc/localtime: adjust zoneinfo according to your needs: + + # ln -sf /usr/share/zoneinfo/$WHATEVER_YOU_WANT /etc/localtime + + The zoneinfo directory contains the time zone files that were + compiled by zic. The files contain information such as rules + about DST. They allow the kernel to convert UTC UNIX time into + appropriate local dates and times. Use the zdump utility to + print current time and date (in the specified time zone). + +* /etc/adjtime: This file is used e.g. by the adjtimex function, + which can smoothly adjust system time while the system runs + +* If you change the time (using 'date --set ...', ntpdate,...) + it is worth setting also the hardware clock to the correct time: + + # hwclock --systohc [--utc] + + Remember to add the --utc -option if the hardware clock is set + to UTC! + +Still problems? +--------------- + +Check your current settings via: + + cat /etc/timezone + zdump /etc/localtime + echo $TZ + hwclock --show + grep hwclock /etc/runlevel.conf + grep '^UTC' /etc/default/rc + +Further information: +-------------------- + + hwclock(8) tzselect(1) tzconfig(8) + http://www.debian.org/doc/manuals/system-administrator/ch-sysadmin-time.html + http://wiki.debian.org/TimeZoneChanges +-- +Recorder shellscript session using script: + +% script -t 2>~/upgrade.time -a ~/upgrade.script +% scriptreplay ~/upgrade.time ~/upgrade.script +-- +Test UTF-8 capabilities of terminal: + +wget http://melkor.dnp.fmph.uniba.sk/~garabik/debian-utf8/download/UTF-8-demo.txt.gz +zcat UTF-8-demo.txt.gz + +or: + +wget http://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt +cat UTF-8-test.txt +-- +UTF-8 at grml / some general information regarding Unicde/UTF-8: + + http://wiki.grml.org/doku.php?id=utf8 +-- + +This allows one ssh connection attepmt per minute per source ip, with a initial +burst of 10. The available burst is like a counter which is initialised with +10. Every connection attempt decrements the counter, and every minute where the +connection limit of one per minute is not overstepped the counter is +incremented by one. If the burst counter is exhausted the real rate limit +comes into play. This gives you 11 connectionattepmts in the first minute +before blocked for 10minutes. After 10 minutes block the game restarts. + +Hint: you could set the burst value to 5 and the block time to only 5 minutes +to achive the same average connection rate but with halve the block time. + +iptables -A inet_in -p tcp --syn --dport 22 -m hashlimit --hashlimit-name ssh \ + --hashlimit 1/minute \ --hashlimit-burst 10 --hashlimit-mode srcip \ + --hashlimit-htable-expire 600000 -j ACCEPT +iptables -A inet_in -p tcp --dport 22 -m state --state NEW -j REJECT +-- +Tunnel a specific connection via socat: + +On the client: +% socat TCP4-LISTEN:8003 TCP4:gateway:500 + +On the gateway: +# socat TCP4-LISTEN:500,fork TCP4:target:$PORT + +Using localhost:8003 on the client uses the tunnel now. +-- +Set date: + +# date --set=060916102007 + +where the bits are month(2)/day(2)/hour(2)/minute(2)/year(4) + +Set date using a relative date: + +# date -s '+3 mins' + +or + +# date -s '+tomorrow' + +Display a specific relative date: + +# date -d '+5 days -2 hours' + +Don't forget to set hardware clock via: + +# hwlock -w +-- +Booting grml via network / PXE: + +Start grml-terminalserver on a system with network access +and where grml is running: + +# grml-terminalserver + +Then booting your client(s) via PXE should work without +any further work. + +See: man grml-terminalserver + http://grml.org/terminalserver/ +-- +Debugging SSL communications: + +% openssl s_client -connect server.adress:993 > output_file +% openssl x509 -noout -text -in output_file + +or + +# ssldump -a -A -H -i eth0 + +See http://prefetch.net/articles/debuggingssl.html for more details. +-- +Remove bootmanager from MBR: + +# lilo -M /dev/hda -s /dev/null +-- +Rewrite grub to MBR: + +# mount /mnt/sda1 +# grub-install --recheck --no-floppy --root-directory=/mnt/sda1 /dev/sda +-- +Rewrite lilo to MBR: + +# mount /mnt/hda1 +# lilo -r /mnt/hda1 +-- +Create screenshot of plain/real console - tty1: + +# fbgrab -c 1 screeni.png +-- +Create screenshot when running X: + +% scrot + +Tip: use the gkrellshoot plugin when using gkrellm +-- +Redirect all connections to hostA:portA to hostB:portB, where hostA and hostB are +different networks: + +Run the following commands on hostA: + +echo 1 > /proc/sys/net/ipv4/ip_forward +iptables -t nat -A PREROUTING -p tcp --dport portA -j DNAT --to hostB:portB +iptables -A FORWARD -i eth0 -o eth0 -d hostB -p tcp --dport portB -j ACCEPT +iptables -A FORWARD -i eth0 -o eth0 -s hostB -p tcp --sport portB -j ACCEPT +iptables -t nat -A POSTROUTING -p tcp -d hostB --dport portB -j SNAT --to-source hostA +-- +Flash BIOS without DOS/Windows: + +Dump flash info and set the flash chip to writable: +# flashrom + +Backup the original BIOS: +# flashrom -r backup.bin + +Notice: the following step will overwrite your current BIOS! +So make sure you really know what you are doing. + +Flash the BIOS image: +# flashrom -wv newbios.bin + +Also check out LinuxBIOS: http://linuxbios.org/ +-- +Enable shadow passwords: + +# shadowconfig on +-- +Set up an IPv6 tunneln on grml: + +# ipv6-tunnel start +-- +Set up console newsreader slrn for use with Usenet: + +% grml-slrn +-- +Calculate with IPv6 addresses: + +% ipv6calc + +For usage examples refer to manpage ipv6calc(8). +-- +Common network debugging tools for use with IPv6: + +% ping6 +% tracepath6 +% traceroute6 +% tracert6 +% nc6 +% tcpspray6 +-- +Set up NFS (Network File System): + +Server-side +~~~~~~~~~~~ +Make sure the relevant services are running on the server side: + +# /etc/init.d/portmap start +# /etc/init.d/nfs-common start +# /etc/init.d/nfs-kernel-server start + +Export shares via /etc/exports: + +/backups 192.168.1.100/24(rw,wdelay,no_root_squash,async,subtree_check) + +... or manually export a directory running: + +# exportfs -o rw,wdelay,no_root_squash,async,subtree_check 192.168.1.100:/backups + +and unexport a share running: + +# exportfs -u 192.168.1.100:/backups + +and every time when you modify /etc/exports file run + +# exportfs -ra + +Display what NFS components are running: + +# rpcinfo -p + +Display list of exported shares: + +# exportfs -v +or +# showmount -e + +Client-side +~~~~~~~~~~~ +Make sure the relevant services are running on the client side: + +# /etc/init.d/portmap start +# /etc/init.d/nfs-common start + +Verify that the server allows you to access its RPC/NFS services: + +# rpcinfo -p server_name + +Check what directories the server exports: + +# showmount -e server_name + +On the client side you can use something like the following in /etc/fstab: + +192.168.1.101:/backups /mnt/nfs nfs defaults,users,wsize=8192,rsize=8192 0 0 +-- +Mount a cloop file: + +# aptitude install cloop-src +# m-a a-i cloop-src + +# modprobe cloop file=/path/to/cloop/file +# mount -r -t iso9660 /dev/cloop /mnt/test +-- +Create a PS/PDF of a plaintext file: + +% a2ps --medium A4dj -E -o output.ps input_file +% ps2pdf output.ps +-- +Print two pages on one in a PDF file: + +% pdfnup --nup 2x1 input.pdf + +Concatenate, extract pages/parts, encrypt/decrypt, +compress PDFs using 'pdftk'. +-- +Read a PS/PDF file on console: + +% pstotext file.pdf + +or on plain framebuffer console in graphical mode: + +% pdf2ps file.pdf ; ps2png file.ps file.png ; fbi file.png + +or + +% fbgs file.pdf +-- +Bypass the password of a PDF file: + +% gs -q -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=output.pdf input.pdf -c quit +-- +Record sound: + +% rec test.aiff + +This will record a AIFF audio file. +-- +Change passphrase / password of an existing SSH key: + +% ssh-keygen -p +-- +Enable syntax highlighting in nano: + +Just uncomment the include directives for your respective +language at the bottom of the file /etc/nanorc +-- +Create netboot package for grml-terminalserver: + +# sh /usr/share/doc/grml-terminalserver/examples/create-netboot +-- +To boot grml via network (PXE) check out grml-terminalserver: + +# grml-terminalserver + +See http://grml.org/terminalserver/ for more details. +-- +Rotate pictures: + +Using the 'Orientation' tag of the Exif header, rotate +the image so that it is upright: +% jhead -autorot *.jpg + +Manually rotate a picture: +% convert -rotate 270 input.jpg output.jpg +-- +Rename files based on the information inside their exif header: + +% jhead -n%Y-%m-%d_%Hh%M_%f *.jpg + +This will rename a file named img_2071.jpg to something like: + +2007-08-17_10h38_img_2071.jpg + +if it was shot at 10:38 o'clock on 2007-08-17 (according to +the information inside the exif header). +-- +Calculate network / netmask: + +Usage examples: +% ipcalc 10.0.0.28 255.255.255.0 +% ipcalc 10.0.0.0/24 +-- +Blacklist a kernel module: + +# blacklist + +-> running 'blacklist hostap_cs' for example will generate an +entry like this in /etc/modprobe.d/grml: + +blacklist hostap_cs +alias hostap_cs off + +To remove the module from the blacklist again just invoke: + +# unblacklist + +or manually remove the entry from /etc/modprobe.d/grml. +-- +Create a Debian package of a perl module: + +% dh-make-perl --cpan Acme::Smirch --build +-- +The Magic SysRq Keys (SysReq or Sys Req, short for System Request): + +To reboot your system using the SysRq keys just hold down the Alt and +SysRq (Print Screen) key while pressing the keys REISUB ("Raising +Elephants Is So Utterly Boring"). + +R = take the keyboard out of raw mode +E = terminates all processes (except init) +I = kills all processes (except init) +S = synchronizes the disk(s) +U = remounts all filesystems read-only +B = reboot the system + +Notice: use O instead of B for poweroff. + +Or write the sequence to /proc/sysrq-trigger instead: + +# for i in r e i s u b ; do echo $i > /proc/sysrq-trigger ; done + +To enable or disable SysRq calls: + +# echo 0 > /proc/sys/kernel/sysrq +# echo 1 > /proc/sys/kernel/sysrq + +See http://en.wikipedia.org/wiki/Magic_SysRq_key for more details. +-- +Memtest / memcheck: + +Just boot your grml Live-CD with "memtest" to execute a memcheck/memtest +with Memtest86+. +-- +Tunnel TCP-Traffic through DNS using dns2tcp: + +Server-side: +~~~~~~~~~~~~ +1. Create necessary DNS-Records: +dnstun.example.com. 3600 IN NS host.example.com. +dnstun.example.com. 3600 IN A 192.168.1.1 +host.example.com. 3600 IN A 192.168.1.1 + +2. Configure dns2tcpd on host.example.com.: +# cat /etc/dns2tcpd.conf +listen = 192.168.1.1 #the ip dns2tcpd should listen on +port = 53 #" port " " " " +user = nobody +chroot = /tmp +domain = dnstun.example.com. # the zone as specified inside dns +ressources = ssh:127.0.0.1:22 # available resources + +3. Start the daemon: +# cat > /etc/default/dns2tcp << EOF +# Set ENABLED to 1 if you want the init script to start dns2tcpd. +ENABLED=1 +USER=nobody +EOF +# /etc/init.d/dns2tcp start + +Client-side: +~~~~~~~~~~~~ +You have two possibilities: +- Use the DNS inside your network (DNS must allow resolving for external domains) +# grep nameserver /etc/resolv.conf +nameserver 172.16.42.1 +# dns2tcpc -z dnstun.example.com 172.16.42.1 +Available connection(s) : + ssh +# dns2tcpc -r ssh -l 2222 -z dnstun.example.com 172.16.42.1 & +Listening on port : 2222 +# ssh localhost -p 2222 +user@host.example.com:~# + +- Directly contact the endpoint (port 53 UDP must be allowed outgoing) +# dns2tcpc -z dnstun.example.com dnstun.example.com +Available connection(s) : + ssh +# dns2tcpc -r ssh -l 2222 -z dnstun.example.com dnstun.example.com & +Listenning on port : 2222 +# ssh localhost -p 2222 +user@host.example.com:~# + +Notice: using 'ssh -D 8080 ..' you will get a socks5-proxy listening on +localhost:8080 which you can use to tunnel everything through your "dns-uplink". +-- +Configure a MadWifi device for adhoc mode: + +Disable the autocreation of athX devices: +# echo "options ath_pci autocreate=none" > /etc/modprobe.d/madwifi + +Remove the autocreated device for now: +# wlanconfig ath0 destroy + +Configuration in /etc/network/interfaces: + +iface ath0 inet static + madwifi-base wifi0 + madwifi-mode adhoc + ... + +Hints: + - Do not use interface names without ending 0 (otherwise startup fails). + - Only chooss unique names for interfaces. +--