Commands using head (314)

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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

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

Convert any sequence of spaces/tabs to single space/tab
Remove empty lines additionally: $ tr -s ' \t\n' 2.txt identical with: $ tr -s '[:space:]' 2.txt To "clean perfectly" a text or code file, You can combine this command with another one: $ while read l; do echo -e "$l"; done 2.txt (= remove all leading and trailing spaces or tabs from all lines of a text file)

Exclude svn directories with grep
exclude-dir option requires grep 2.5.3

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Create incremental backups of individual folders using find and tar-gzip
Problem: I wanted to backup user data individually, using and incremental method. In this example, all user data is located in "/mnt/storage/profiles", and about 25 folders inside, each with a username ( /mnt/storage/profiles/mike; /mnt/storage/profiles/lucy ...) I need each individual folder backed up, not the whole "/mnt/storage/profiles". So, using find while excluding directories depth and creating two variables (tarfile=username & desdir=destination), tar will create a .tgz file for each folder, resulting in a "mike_2013-12-05.tgz" and "lucy_2013-12-05.tgz".

Undo commit in Mercurial

Converts multiple youtube links to mp3 files
Usage: ytmp3 "YTurl" "YTurl2" "YTurl3" "YTurlN" Uses the shift command to let you extract the .mp3 from as many youtube urls as you like (or wherever else youtube-dl is supported) *Requires youtube-dl Orginal chunk of code: youtube-dl -q -t --extract-audio --audio-format mp3 URL taken from here http://www.commandlinefu.com/commands/view/9701/convert-youtube-videos-to-mp3

Display all shell functions set in the current shell environment
Uses the shell builtin `declare` with the '-f' flag to output only functions to grep out only the function names. You can use it as an alias or function like so: alias shfunctions="builtin declare -f | command grep --color=never -E '^[a-zA-Z_]+\ \(\)'" shfunctions () { builtin declare -f | command grep --color=never -E '^[a-zA-Z_]+\ \(\)'; }

Run a command as root, with a delay
$ sleep 1h ; sudo command or $ sudo sleep 1h ; sudo command won't work, because by the time the delay is up, sudo will want your password again.


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