X-Git-Url: http://git.grml.org/?a=blobdiff_plain;f=grml_tips;h=4fa526361d41e0573e0c2fbaf905600fa4fb113c;hb=4c8e7332cd1a7b92a85de64d90273ad5845821df;hp=2d96b61d489d31f9b519dcd4ce194f25fcafd0cc;hpb=cb61efe22438483247917bc02f3490ad4d435eb1;p=grml-tips.git diff --git a/grml_tips b/grml_tips index 2d96b61..4fa5263 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 @@ -663,7 +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' -- @@ -1094,7 +1090,7 @@ Avoid all of the above steps - use grml-debootstrap(8) instead! -- 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: @@ -1278,8 +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 @@ -1294,8 +1289,32 @@ 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 + +To get a list of available providers execute: + +# gcom -s -d /dev/ttyUSB0 /usr/share/doc/gcom/examples/operator -- hdparm - get/set hard disk parameters @@ -2631,10 +2650,13 @@ and where grml is running: 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 +% openssl s_client -connect server.adress:993 > output_file +% openssl x509 -noout -text -in output_file or @@ -2783,3 +2805,286 @@ Mount a cloop file: # 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. +-- +Find dangling symlinks using zsh: + +% ls **/*(-@) +-- +Use approx with runit supervision +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Install the packages: +# apt-get install approx runit + +Add user approxlog for the logging daemon: +# adduser --system --home /nonexistent --no-create-home approxlog + +Create config directory: +# mkdir /etc/sv/approx + +Use /var/run/sv.approx as supervise directory: +# ln -s /var/run/sv.approx /etc/sv/approx/supervise + +# cat > /etc/sv/approx/run << EOF +#!/bin/sh +echo 'approx starting' +exec approx -f 2>&1 +EOF + +You normally do not need a logging service for approx because it logs +to syslog too. So just for completion: +# mkdir -p /etc/sv/approx/log +# ln -s /var/run/sv.approx.log /etc/sv/approx/log/supervise +# cat > /etc/sv/approx/log/run << EOF +#!/bin/sh +set -e +LOG="/var/log/approx" +test -d "$LOG" || mkdir -p -m2750 "$LOG" && chown approxlog:adm "$LOG" +exec chpst -uapproxlog svlogd -tt -v "$LOG" +EOF + +Now activate the new approx service (will be started within 5s): +# ln -s /etc/sv/approx/ /var/service/ + +Make approx managed via runit available via init-script interface: +# dpkg-divert --local --rename /etc/init.d/approx +# ln -s /usr/bin/sv /etc/init.d/approx +-- +Remote-reboot a grml system using SysRQ via /proc (execute as root): + +eject &>/dev/null +umount -l /cdrom +eject /dev/cdrom +echo b > /proc/sysrq-trigger +-- +Show what happens on /dev/sda0: + +# mount the debugfs to relay kernel info to userspace +mount -t debugfs none /sys/kernel/debug + +# is a convenient wrapper arround blktrace and blkparse +btrace /dev/sda0 +-- +Convert Flash to Avi: + +% ffmpeg -i input.flv output.avi +-- +Usage example for cryptsetup / -luks encrypted partition on LVM: + +volume group name: x61 +logical volume name: home + +echo "grml-crypt_home /dev/mapper/x61-home none luks" >> /etc/crypttab +Start cryptdisks +mount /dev/mapper/grml-crypt_home /mnt/test +-- +fdisk/parted/... complains with something like +'unable to open /dev/sda - unrecognised disk label'?! + +See http://grml.org/faq/#fdisk => + +* use /sbin/fdisk.distrib from util-linux +* switch to sfdisk, cfdisk,... +* use parted's mklabel command (but please read the + parted manual before executing this command) +--