Commands by dudko (4)

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Randomize lines (opposite of | sort)
random(6) - random lines from a file or random numbers

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

Lists installed kernels

Cut the first 'N' characters of a line
Saves one character, the original is probably clearer

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" }

What is my public IP-address?
Short command, easy to remember

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

remove comments (even those starting with spaces), empty lines (even those containing spaces) in one grep command
useful for discarding even those comments which start with blanks or those empty lines which contain blanks

Change every instance of OLD to NEW in file FILE
Very quick way to change a word in a file. I use it all the time to change variable names in my PHP scripts (sed -i 's/$oldvar/$newvar/g' index.php)

clean up memory on linux
where proc filesystem mounted under /proc


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