Commands tagged bash (821)

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Get a list of the top 10 heaviest tables in your mysql database - useful for performance diagnostics

locating packages held back, such as with "aptitude hold "
locating packages held back, such as with "aptitude hold "

Block all IP addresses and domains that have attempted brute force SSH login to computer
I use iptables. To rate limit connections. Very easy and no ban lists to manage.

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines
A variation of a script I found on this site and then slimmed down to just use awk. It displays all users who have attempted to login to the box and failed using SSH. Pipe it to the sort command to see which usernames have the most failed logins.

Sort contents of a directory with human readable output
Show sizes of all files and directories in a directory in size order. $du -hs * | sort -hr for reverse order. Taken from http://serverfault.com/questions/62411/how-can-i-sort-du-h-output-by-size

nohup that doesn't generate nohup.out
I'm sure this can be piped into another way. Please share!

Get information about memory modules
To take information about the characteristics of the installed memory modules.

delete a line from your shell history
If you're a moron like me, sometimes your fingers get away from you and you, for example, enter your password when you're already authenticated to ssh-agent, sudo, etc., and your password ends up in shell history. Here's how to get it out.

Function to check whether a regular file ends with a newline
tail -c 1 "$1" returns the last byte in the file. Command substitution deletes any trailing newlines, so if the file ended in a newline $(tail -c 1 "$1") is now empty, and the -z test succeeds. However, $a will also be empty for an empty file, so we add -s "$1" to check that the file has a size greater than zero. Finally, -f "$1" checks that the file is a regular file -- not a directory or a socket, etc.


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