Commands by lv4tech (10)

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echo something backwards
NAME rev - reverse lines of a file or files SYNOPSIS rev [file ...] DESCRIPTION The rev utility copies the specified files to the standard output, reversing the order of characters in every line. If no files are specified, the standard input is read. AVAILABILITY The rev command is part of the util-linux-ng package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.

Rename files to be all in CAPITALS
Simple bash/ksh/sh command to rename all files from lower to upper case. If you want to do other stuff you can change the tr command to a sed or awk... and/or change mv to cp....

list block devices
Shows all block devices in a tree with descruptions of what they are.

[vim] Clear a file in three characters (plus enter)
% selects every line in the file. 'd' deletes what's selected. It's a pretty simple combination.

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

Kill all processes belonging to a user
This is a 'killall' command equivalent where it is not available. Prior to executing it, set the environment variable USERNAME to the username, whose processes you want to kill or replace the username with the $USERNAME on the command above. Side effect: If any processes from other users, are running with a parameter of $USERNAME, they will be killed as well (assuming you are running this as root user) [-9] in square brackets at the end of the command is optional and strongly suggested to be your last resort. I do not like to use it as the killed process leaves a lot of mess behind.

archive all files containing local changes (svn)
Create a tgz archive of all the files containing local changes relative to a subversion repository. Add the '-q' option to only include files under version control: $svn st -q | cut -c 8- | sed 's/^/\"/;s/$/\"/' | xargs tar -czvf ../backup.tgz Useful if you are not able to commit yet but want to create a quick backup of your work. Of course if you find yourself needing this it's probably a sign you should be using a branch, patches or distributed version control (git, mercurial, etc..)

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" }

Edit a file in vim (at the first error) if it is not well formed xml.
Validate a file using xmllint. If there are parser errors, edit the file in vim at the line of the first error.

Log your internet download speed
This will log your internet download speed. You can run $gnuplot -persist


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