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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"

Google URL shortener
(1) required: python-googl ( install by: pip install python-googl ) (2) get from google API console https://code.google.com/apis/console/

Find ulimit values of currently running process
When dealing with system resource limits like max number of processes and open files per user, it can be hard to tell exactly what's happening. The /etc/security/limits.conf file defines the ceiling for the values, but not what they currently are, while $ ulimit -a will show you the current values for your shell, and you can set them for new logins in /etc/profile and/or ~/.bashrc with a command like: $ ulimit -S -n 100000 >/dev/null 2>&1 But with the variability in when those files get read (login vs any shell startup, interactive vs non-interactive) it can be difficult to know for sure what values apply to processes that are currently running, like database or app servers. Just find the PID via "ps aux | grep programname", then look at that PID's "limits" file in /proc. Then you'll know for sure what actually applies to that process.

format txt as table not joining empty columns
-n switch keeps empty columns If your distribution does not ship with a recent column version that supports -n you can use this alternative: perl -pe 's/(^|;);/$1 ;/g' file.csv | column -ts\; | less -S Change the delimiter to your liking.

Get first Git commit hash
https://git.kernel.org/cgit/git/git.git/commit/?id=ad5aeeded3295589b2573b143f754762a56f8f82

convert ascii string to hex
just a bit simpler

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Add "prefix" on a buch of files

Use Dell Service Tag $1 to Find Machine Model [Model Name and Model Number]
255 Max Characters CommandLineFu for $dellurl='http://support.dell.com/support/topics/global.aspx/support/my_systems_info/en/details?c=us&cs=04&l=en&s=hied&ServiceTag='

Wait for file to stop changing
This loop will finish if a file hasn't changed in the last 10 seconds. . It checks the file's modification timestamp against the clock. If 10 seconds have elapsed without any change to the file, then the loop ends. . This script will give a false positive if there's a 10 second delay between updates, e.g. due to network congestion . How does it work? 'date +%s' gives the current time in seconds 'stat -c %Y' gives the file's last modification time in seconds '$(( ))' is bash's way of doing maths '[ X -lt 10 ]' tests the result is Less Than 10 otherwise sleep for 1 second and repeat . Note: Clever as this script is, inotify is smarter.


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