Commands by abracadabra (1)

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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"

Extract raw URLs from a file
you can also use cut instead of awk. less powerful but probably faster. ;)

drop first column of output by piping to this

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.

convert Decimal to IP from stdin
https://stackoverflow.com/questions/10768160/ip-address-converter

Fibonacci With Case
Returns the '$1'th Fibonacci number.

how to export a table in .csv file
Exports the result of query in a csv file

list block devices
Shows all block devices in a tree with descruptions of what they are.

Determine next available UID
Typical usage would be in a script that would want the next open UID in a range (in this case 500-600)

Count opening and closing braces in a string.
This function counts the opening and closing braces in a string. This is useful if you have eg long boolean expressions with many braces and you simply want to check if you didn't forget to close one.

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