Commands by ozymandias (2)

  • In my work environment, we log onto the servers as our user ('user', in the sample ouput), and 'sudo su - root' to other accounts. This trick allows us to return the account name we logged in as -- and not the account name we currently are ('root', in this example). Using this trick, you can build other commands: Set your CVSROOT env variable to your account name: CVSROOT=$(who am i | awk '{print $1}')@cvs.server.example.com:/cvsroot SCP a file to another server: scp file.txt $(who am i | awk '{print $1}')@some.other.server.com:. This works out great in my environment, as we can include this in our documentation and make the comands more easy to copy/paste for different users, and not have to set all sorts of variables, or modify the docs for each user. whoami gives you the name of the user you currently are, not the user you logged on originally as. who gives you a listing of every single person logged onto the server. who am i gives you the name of the user you logged on as, and not who you changed to with su. Look at the following scenario: whoami user su - # whoami root # who am i user pts/51 2009-02-13 10:24 (:0.0) whoami != who am i Show Sample Output


    -18
    who am i
    ozymandias · 2009-02-20 16:26:11 9
  • The expansion {,} in bash will repeat the given string once for each item seperated by commas. The given command will result in the following being run: cp /really/long/path/and/file/name /really/long/path/and/file/name-`date -I` These can be embedded as needed, ex: rm file{1,2,3{1,2,3}} would delete the files file1, file2, file31, file32, file32, and no other files.


    4
    cp /really/long/path/and/file/name{,-`date -I`}
    ozymandias · 2009-02-18 20:35:47 2

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

list files recursively by size

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

Automatically download Ubuntu 10.04 when available
Tested with 9.10 release. Choose whatever torrent client you prefer.

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

Generate 2000 images with its number written on it

JSON processing with Python
Validates and pretty-prints the content fetched from the URL.

validate json
I have this saved as jsonlint chmodded +x and file.js is instead $1, but YMMV

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

Clear your history saved into .bash_history file!
Note the space before the command; that prevents your history eliminating command from being recorded. ' history -c && rm -f ~/.bash_history' Both steps are needed. 'history -c' clears what you see in the history command. 'rm -f ~/.bash_history' deletes the history file in your home directory.

Filter out all blank or commented (starting with #) lines


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: