Commands by jscolaire (1)

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

floating point operations in shell scripts
using bc is for sissies. dc is much better :-D Polish notation will rule the world...

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" }

Advanced python tracing
Trace python statement execution and syscalls invoked during that simultaneously

analyze traffic remotely over ssh w/ wireshark
This captures traffic on a remote machine with tshark, sends the raw pcap data over the ssh link, and displays it in wireshark. Hitting ctrl+C will stop the capture and unfortunately close your wireshark window. This can be worked-around by passing -c # to tshark to only capture a certain # of packets, or redirecting the data through a named pipe rather than piping directly from ssh to wireshark. I recommend filtering as much as you can in the tshark command to conserve bandwidth. tshark can be replaced with tcpdump thusly: $ ssh root@example.com tcpdump -w - 'port !22' | wireshark -k -i -

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"

SSH Auto-login with password
You need to install "sshpass" for this to work. apt-get install sshpass

Prints line numbers
If you don't have nl on your system, this achieves a similar effect, the default behavior in nl is to not number blank lines, but this does.

rename anime fansubs
renames Anime Episodes to files, that can be parsed by sonarr & co

Get the total length of time in hours:minutes:seconds (HH:MM:SS) of all video (or audio) in the current dir (and below)
change the *.avi to whatever you want to match, you can remove it altogether if you want to check all files.

List Network Tools in Linux
Get all the networking related commands for your distro

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: