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Resize A Mounted EXT3 File System
Live extension of an ext3 file system on logical volume $v by 200GB without the need to unmount/remount. Requires that you have 1) a version of resize2fs that contains code merged from ext2online, and 2) kernel support for online resizing. (e.g. RHEL 5)

get all Google ipv4 subnets for a iptables firewall for example
a bit shorter, parenthesis not needed but added for clarity

Customer Friendly free
makes more sense to customers XD

Command to rename multiple file in one go

Skip to next selection in playlist
Uses process signal to play next selection

Generate a random password 30 characters long

Execute a command with a timeout
In this example the command "somecommand" will be executed and sent a SIGALARM signal if it runs for more than 10 seconds. It uses the perl alarm function. It's not 100% accurate on timing, but close enough. I found this really useful when executing scripts and commands that I knew might hang E.g. ones that connect to services that might not be running. Importantly this can be used within a sequential script. The command will not release control until either the command completes or the timeout is hit.

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" }

Encode text in Base64 using Perl
MIME::Base64 is a part of Perl5 distribution. You can also use decode_base64 for oposite result.

Make vim open in tabs by default (save to .profile)
I always add this to my .profile rc so I can do things like: "vim *.c" and the files are opened in tabs.


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