X-Git-Url: http://git.grml.org/?a=blobdiff_plain;f=grml_tips;h=cdb37e80961645dafefea7f9e0e942bffe35ffe7;hb=3afdc13d424d74183874631841ca0d5f949158a7;hp=d8ac68d7c7e715e83f42d8a67a7f0de0b6af5708;hpb=044dc85899d9d3da8bf659f2528169d9ba277b05;p=grml-tips.git diff --git a/grml_tips b/grml_tips index d8ac68d..cdb37e8 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 +657,7 @@ to get a list of all supported trees -- Transfer your SSH public key to another host: -% ssh-keygen # if you don't have a key yet +% 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 @@ -1317,6 +1311,10 @@ product ID when loading the usbserial module. Usage example: 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 @@ -2652,10 +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 @@ -2718,7 +2719,7 @@ Enable shadow passwords: # shadowconfig on -- -Set up an IPv6 tunneln on grml: +Set up an IPv6 tunnel on grml: # ipv6-tunnel start -- @@ -2838,3 +2839,272 @@ Record sound: 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) +-- +dmraid - support for SW-RAID / FakeRAID controllers +like Highpoint HPT and Promise FastTrack + +Activate all software RAID sets discovered: +# dmraid -ay + +Deactivates all active software RAID sets: +# dmraid -an + +Discover all software RAID devices supported on the system: +# dmraid -r +-- +Extract winmail.dat: + +List content: +% ytnef winmail.dat + +Extract files to current directory: +% ytnef -f . winmail.dat +--