Commands by p1ngouin (1)

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cooking a list of numbers for calculation
When you've got a list of numbers each on its row, the ECHO command puts them on a simple line, separated by space. You can then substitute the spaces with an operator. Finally, pipe it to the BC program.

Remove specific versions of old kernels (Ubuntu/Debian)
If, for example, you want to remove all kernels and headers but the last three versions, you can't use one of that magic all-in-one "remove old stuff" commands. With this simple but elegant command you can remove a range of versions, or a list of versions with e.g. {14,16,20}.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Execute a command at a given time
This is an alternative to cron which allows a one-off task to be scheduled for a certain time.

grep across a git repo and open matching files in gedit

Ignore a directory in SVN, permanently
This command allow you to ignore certain directories on SVN commands, like SVN STATUS. It is sad see a lot of temporary files from templates_c for each "svn status", no? ;-) This works only on directories under revision control.

list block devices
Shows all block devices in a tree with descruptions of what they are.

Remove all zero size files from current directory (not recursive)

sum numbers in the file (or stdin)
add integers from the stdin and print out the result usually, cat /tmp/file | echo $(($(tr '\n' '+')0))

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

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