Commands by Giancarlo (3)

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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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Big (four-byte) $RANDOM
Sometimes, in a shell script, you need a random number bigger than the range of $RANDOM. This will print a random number made of four hex values extracted from /dev/urandom.

Print every Nth line (to a maximum)
Thanks to knoppix5 for the idea :-) Print selected lines from a file or the output of a command. Usage: $ every NTH MAX [FILE] Print every NTH line (from the first MAX lines) of FILE. If FILE is omitted, stdin is used. The command simply passes the input to a sed script: $ sed -n -e "${2}q" -e "0~${1}p" ${3:-/dev/stdin} print no output $ sed -n quit after this many lines (controlled by the second parameter) $ -e "${2}q" print every NTH line (controlled by the first parameter) $ -e "0~${1}p" take input from $3 (if it exists) otherwise use /dev/stdin ${3:-/dev/stdin}

Watch your freebox flux, through a other internet connection (for French users)
You can watch channels of your freebox, everywhere. With " vlc http://your-ip:12345 " on the client and ncurses vlc interface on the host. et voila

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

dstat - a mix of vmstat, iostat, netstat, ps, sar...
This is a very powerful command line tool to gather statistics for a Linux system. http://dag.wieers.com/home-made/dstat/

Convert multiple pdf's to jpg in linux using the convert command

comment current line(put # at the beginning)

Find usb device
I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

Extract neatly a rar compressed file
It's also possible to delay the extraction (echo "unrar e ... fi" |at now+20 minutes) wich is really convenient!

remove *.jpg smaller than 500x500


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