Commands by G2G (1)

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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

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" }

list all files in a directory, sorted in reverse order by modification time, use file descriptors.
It's both silly, and infinitely useful. Especially useful in logfile directories where you want to know what file is being updated while troubleshooting.

Release memory used by the Linux kernel on caches
The Linux kernel uses unused memory in caches. When you execute "free" you never get the "real" available memory.

Show current pathname in title of terminal
This helps to keep track of what is going on when you have several tabs open in your terminal. The title automatically changes when you change directories.

Start dd and show progress every X seconds

Rename files in batch

Squish repeated delimiters into one
This can be particularly useful used in conjunction with a following cut command like $echo "hello::::there" | tr -s ':' | cut -d':' -f2 which prints 'there'. Much easier that guessing at -f values for cut. I know 'tr -s' is used in lots of commands here already but I just figured out the -s flag and thought it deserved to be highlighted :)

Easily decode unix-time (funtion)
A shell function using perl to easily convert Unix-time to text. Put in in your ~/.bashrc or equivalent. Tested on Linux / Solaris Bourne, bash and zsh. using perl 5.6 and higher. (Does not require GNU date like some other commands)

Convert any sequence of spaces/tabs to single space/tab
Remove empty lines additionally: $ tr -s ' \t\n' 2.txt identical with: $ tr -s '[:space:]' 2.txt To "clean perfectly" a text or code file, You can combine this command with another one: $ while read l; do echo -e "$l"; done 2.txt (= remove all leading and trailing spaces or tabs from all lines of a text file)


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