Commands by poojasharma08 (0)

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Change newline to space in a file just using echo
Changing newline to spaces using just echo

Pipe STDOUT to vim
The hyphen tells vim to open from STDOUT - saves having to create temporary files.

Scan Subnet for IP and MAC addresses

display a smiling smiley if the command succeeded and a sad smiley if the command failed
you could save the code between if and fi to a shell script named smiley.sh with the first argument as and then do a smiley.sh to see if the command succeeded. a bit needless but who cares ;)

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" }

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"

List files older than one year, exluding those in the .snapshot directory
Useful when you want to cron a daily deletion task in order to keep files not older than one year. The command excludes .snapshot directory to prevent backup deletion. One can append -delete to this command to delete the files : $ find /path/to/directory -not \( -name .snapshot -prune \) -type f -mtime +365 -delete

pretend to be busy in office to enjoy a cup of coffee
The first parameter after timeout is the key parameter; number of seconds to wait. With a 6 you have 600 seconds for your coffee break (10min).

Screenshot pipe to remote host, adding URL to clipboard, notifying when done. (without saving locally)
Requires you to have password free login to remote host ;) Requires xclip and notify-send (If you want to put into clipboard and be notified when action is completed). DATE=$(date +%Y-%m-%d_%H-%M-%S)-$(($(date +%N)/10000000)); HOST="ssh host of your choice"; DEST="destination folder without trailing slash"; URL="URL for file if uploaded to web enabled dir ie. http://$HOST/~user/screenshot_$DATE.png"; import -window root png:- | ssh $HOST "cat > $DEST/screenshot_$DATE.png"; echo $URL | xclip; notify-send -u low "Screenshot Taken" "Entire screen.\nCopied to clipboard"

Multi-line grep
Using perl you can search for patterns spanning several lines, a thing that grep can't do. Append the list of files to above command or pipe a file through it, just as with regular grep. If you add the 's' modifier to the regex, the dot '.' also matches line endings, useful if you don't known how many lines you need are between parts of your pattern. Change '*' to '*?' to make it greedy, that is match only as few characters as possible. See also http://www.commandlinefu.com/commands/view/1764/display-a-block-of-text-with-awk to do a similar thing with awk. Edit: The undef has to be put in a begin-block, or a match in the first line would not be found.

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