All commands (14,187)

What's this?

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.

Share Your Commands


Check These Out

Backup all mysql databases to individual files on a remote server
It grabs all the database names granted for the $MYSQLUSER and gzip them to a remote host via SSH.

Put a console clock in top right corner
This puts a clock in the top right of the terminal. This version doesn't use tput, but uses escape codes

add static arp entry to default gateway, arp poison protection

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" }

diff two unsorted files without creating temporary files
bash/ksh subshell redirection (as file descriptors) used as input to diff

Quickly get summary of sizes for files and folders
Use this as a quick and simple alternative to the slightly verbose "du -s --max-depth=1"

shut of the screen.

See a full last history by expanding logrotated wtmp files
When your wtmp files are being logrotated, here's an easy way to unpack them all on the fly to see more than a week in the past. The rm is the primitive way to prevent symlink prediction attack.

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"

Buffer in order to avoir mistakes with redirections that empty your files
A common mistake in Bash is to write command-line where there's command a reading a file and whose result is redirected to that file. It can be easily avoided because of : 1) warnings "-bash: file.txt: cannot overwrite existing file" 2) options (often "-i") that let the command directly modify the file but I like to have that small function that does the trick by waiting for the first command to end before trying to write into the file. Lots of things could probably done in a better way, if you know one...


Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: