javabridger / Useful-Linux-Commands

Just a place for me to keep commands that I occasionally need but can never remember

Helpful Linuxiness

Find the biggest files and directories

du -Sh | sort -rh | head -n 15 

http://ask.xmodulo.com/find-biggest-files-directories-linux.html

Touch all files in a directory

find . -exec touch {} \+

http://unix.stackexchange.com/questions/22291/touch-all-folders-in-a-directory

Count Files in a Directory

ls -l | wc -l

Get total directory size

du -hs /path/to/directory

http://askubuntu.com/questions/1224/how-do-i-determine-the-total-size-of-a-directory-folder-from-the-command-line

chmod Number Codes

0 == --- == no access
1 == --x == execute
2 == -w- == write
3 == -wx == write / execute
4 == r-- == read
5 == r-x == read / execute
6 == rw- == read / write
7 == rwx == read / write / execute

Adding alias's to bashrc

vi ~/.bashrc

	alias ll='ls-al'
	:wq

source ~/.bashrc

Find Installed RPM

rpm -qa |grep -i <rpm>

Note: The -i on grep will ignore case

Get RPM scripts

rpm -qp --scripts MySQL-server-5.6.23-1.el6.i686.rpm > /tmp/scripts

From: http://help.lockergnome.com/linux/extract-pre-post-scripts-binary-rpm--ftopict418302.html

Bash Comparison Operators

-gt

http://tldp.org/LDP/abs/html/comparison-ops.html

Extracting Files from RPM

mkdir rpm
cd rpm
<place rpm to extract here>
rpm2cpio <rpm-name> | cpio -idmv

From: http://www.cyberciti.biz/tips/how-to-extract-an-rpm-package-without-installing-it.html