Commands by mrg2k8 (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

Remind yourself every 15 minutes (repeated reminders)
Note: 1) -n option of watch accepts seconds 2) -t option of notify-send accepts milliseconds 3) All quotes stated in the given example are required if notification message is more than a word. 4) I couldn't get this to run in background (use of & at the end fails). Any suggestions/improvements welcome.

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

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"

Turn shell tracing and verbosity (set -xv) on/off with 1 command!
Running this command turns shell tracing and shell verbose debugging on or off. Not only does it do that, it also uses your terminals builtin method of setting colors to make debugging much easier. It looks at the current shell options contained in the $- special bash variable and that lets this function set the opposite of the current value. So from the shell you could do a: $ setx; echo "y" | ( cat -t ) | echo "d"; setx and it will turn on debbuggin. This is an amazingly useful function that is perfect to add system-wide by adding it to /etc/profile or /etc/bashrc.. You can run it from the shell, and you can also use it in your shell scripts like my .bash_profile - http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Get CPU thermal data on MacOS

Unaccent an entire directory tree with files.
This command changes all filename and directories within a directory tree to unaccented ones. I had to do this to 'sanitize' some samba-exported trees. The reason it works might seem a little difficult to see at first - it first reverses-sort by pathname length, then it renames only the basename of the path. This way it'll always go in the right order to rename everything. Some notes: 1. You'll have to have the 'unaccent' command. On Ubuntu, just aptitude install unaccent. 2. In this case, the encoding of the tree was UTF-8 - but you might be using another one, just adjust the command to your encoding. 3. The program might spit a few harmless errors saying the files are the same - not to fear.

One-liner to generate Self-Signed SSL Certificate+Key without any annoying prompts or CSRs
Handy if you want to quickly generate a self-signed certificate. Also can be used in your automated scripts for generating quick-use certificates.

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" }

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


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: