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Read and write to TCP or UDP sockets with common bash tools
Ever needed to test firewalls but didn't have netcat, telnet or even FTP? Enter /dev/tcp, your new best friend. /dev/tcp/(hostname)/(port) is a bash builtin that bash can use to open connections to TCP and UDP ports. This one-liner opens a connection on a port to a server and lets you read and write to it from the terminal. How it works: First, exec sets up a redirect for /dev/tcp/$server/$port to file descriptor 5. Then, as per some excellent feedback from @flatcap, we launch a redirect from file descriptor 5 to STDOUT and send that to the background (which is what causes the PID to be printed when the commands are run), and then redirect STDIN to file descriptor 5 with the second cat. Finally, when the second cat dies (the connection is closed), we clean up the file descriptor with 'exec 5>&-'. It can be used to test FTP, HTTP, NTP, or can connect to netcat listening on a port (makes for a simple chat client!) Replace /tcp/ with /udp/ to use UDP instead.

Install pip with Proxy
Installs pip packages defining a proxy

Start a game on the discrete GPU (hybrid graphics)
On laptops featuring hybrid graphics and using the free X drivers, the DRI_PRIME variable indicates which GPU to run on. This alias allows to utilize the faster discrete GPU without installing proprietary drivers.

Retrieve the size of a file on a server
- Where $URL is the URL of the file. - Replace the $2 by $3 at the end to get a human-readable size. Credits to svanberg @ ArchLinux forums for original idea. Edit: Replaced command with better version by FRUiT. (removed unnecessary grep)

Discovering all open files/dirs underneath a directory
It may be helpful in case you need to umount a directory and some process is preventing you to do so keeping the folder busy. The lsof may process the +D option slowly and may require a significant amount of memory because it will descend the full dir tree. On the other hand it will neither follow symlinks nor other file systems.

Fetch the current human population of Earth
Fetches the world population JSON data from the US census and parses it uses jshon

return a titlecased version of the string[str.title() in python]

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

How much RAM is Apache using?
Display the amount of memory used by all the httpd processes. Great in case you are being Slashdoted!

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


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