Commands by userevolution (5)

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Rename files in batch

Start a terminal with three open tabs
If you launch gnome-terminal manually, you can start with three open tabs

generate 30 x 30 matrix
or $ od /dev/urandom -w60 -An|sed 's/ ..../ /g'|head -n 30 (this one lacks digits 8 and 9)

Make sudo forget password instantly
By default sudo 'remembers' password for a few minutes, so that you do not need to re-enter password for a series of sudo commands that might follow within a short time duration. However, sometime you might want sudo to instantly 'forget' the password. (Next sudo command will need you to reenter the password) Credit: I first learned this while listening to one of the 'tuxradar' podcast.

grep tab chars
mixing tabs and spaces for indentation in python would confuse the python interpreter, to avoid that, check if the file has any tab based indentation. "^V" => denotes press control + v and press tab within quotes. $ cat improper_indent.py class Tux(object): print "Hello world.." $ grep " " improper_indent.py print "Hello world.."

Using netcat to copy files between servers
It bypasses encryption overhead of SSH and depending on configuration can be significantly faster. It's recommended to use only in trusted networks.

"Pretty print" $PATH, show directories in $PATH, one per line with replacement pattern using shell parameter expansion
Can be used to create path alias. From: https://www.cyberciti.biz/tips/bash-aliases-mac-centos-linux-unix.html. #9

find all file larger than 500M

check open ports without netstat or lsof

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"


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