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find distro name / release version

Load all files (including in subdirs), whose name matches a substring, into Vim
This command searches the current directory, and all of its subdirs, for files that have the string "foo" in their filename (foo.c, two-foo.txt, index-FOO-bar.php, etc), and opens them in Vim. It ignores any hidden .svn directories. Change -iname to -name if you want to do case-sensitive matches. Files open in buffers by default, so to verify that the correct files were opened, type ":list". You can load all the files in tabs by doing ":tab ball" or use 'vim -p' on the command-line to load files straight to tabs. If you get permission denied errors, do: vim $(find . ! -path \*.svn\* -type -f iname \*foo\* 2>/dev/null) To narrow it down to a single file extension, such as .php files, use \*foo\*.php (or '*foo*.php'. Which ever you prefer)

File rotation without rename command
Rotates log files with "gz"-extension in a directory for 7 days and enumerates the number in file name. i.e.: logfile.1.gz > logfile.2.gz I needed this line due to the limitations on AIX Unix systems which do not ship with the rename command.

TCP and UDP listening sockets
This command show listening sockets TCP and UDP. Useful for stop unwanted services from linux.

test for ksh/bash
Dave Korn gave me this one. It works because ksh allows variable names ( w/o the $name syntax ) used by sh and bash. I wrote it to permit "single source" shell libraries; the current objective: every shell library may be sourced by either shell. see http://github.com/applemcg/backash

Securely destroy data (including whole hard disks)
GNU shred is provided by the coreutils package on most Linux distribution (meaning, you probably have it installed already), and is capable of wiping a device to DoD standards. You can give shred any file to destroy, be it your shell history or a block device file (/dev/hdX, for IDE hard drive X, for example). Shred will overwrite the target 25 times by default, but 3 is enough to prevent most recovery, and 7 passes is enough for the US Department of Defense. Use the -n flag to specify the number of passes, and man shred for even more secure erasing fun. Note that shredding your shell history may not be terribly effective on devices with journaling filesystems, RAID copies or snapshot copies, but if you're wiping a single disk, none of that is a concern. Also, it takes quite a while :)

shows history of logins on the server
outputs a history of logins on the server (top 10, when piped to 'head'); optional flags: '-a' put the hostname at the end of the line (good for long hostnames), '-i' post the IP instead of the hostname, '-F' put the full login and logout times, rather than short times.

print DateTimeOriginal from EXIF data for all files in folder
see output from `identify -verbose` for other keywords to filter for (e.g. date:create, exif:DateTime, EXIF:ExifOffset).

Multi-thread any command
For instance: $ find . -type f -name '*.wav' -print0 |xargs -0 -P 3 -n 1 flac -V8 will encode all .wav files into FLAC in parallel. Explanation of xargs flags: -P [max-procs]: Max number of invocations to run at once. Set to 0 to run all at once [potentially dangerous re: excessive RAM usage]. -n [max-args]: Max number of arguments from the list to send to each invocation. -0: Stdin is a null-terminated list. I use xargs to build parallel-processing frameworks into my scripts like the one here: http://pastebin.com/1GvcifYa

Monitor iptables in realtime


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