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commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Video thumbnail
Faster thumbnail creation than '-itsoffset' $ffmpeg -itsoffset -4 -i test.avi -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320x240 test.jpg

Watch contents of a file grow
In this case, I'm keeping an eye on /var/log/messages, but of course any file will do. When I'm following a file, I generally don't want to see anything other than what has been added due to the command or service I've executed. This keeps everything clean and tidy for troubleshooting.

Bash: escape '-' character in filename
If you don't escape the - of the filename, you will get the command interpreting it as a parameter, returning (in the best case) an error.

vim easter egg
inside vim try: :help 42 to get the meaning of life, the universe and everything !

Safe Russian Roulette (only echo, don't delete files)
Shows "Bang!" in a chance of 1 out of 6, like in the original game with the gun (spin every round). Otherwise, echoes "Click...". If feeling brave you can also do: $[ $[ $RANDOM % 6 ] == 0 ] && echo 'Bang!' && a really killer command || echo 'Click...'

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

check open ports without netstat or lsof

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

convert Decimal to IP from stdin
https://stackoverflow.com/questions/10768160/ip-address-converter

check for write/read permissions
su www-apache/ftp user and then check readable: find ~/ -type d \( -wholename '/dev/*' -o -wholename '/sys/*' -o -wholename '/proc/*' \) -prune -o -exec test -r {} \; -exec echo {} readable \; 2>/dev/null check writable: find ~/ -type d \( -wholename '/dev/*' -o -wholename '/sys/*' -o -wholename '/proc/*' \) -prune -o -exec test -w {} \; -exec echo {} writable \; 2>/dev/null


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