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Copy the text from the 3rd line to the 9th line into a new file with VI

Poor man's ntpdate
If you don't have netcat, you can use curl.

which program is this port belongs to ?
Sometimes you need to use a port that is already opened by some program , and you don't know who to "kill" for it to release - so, now you do !

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"

Avoids ssh timeouts by sending a keep alive message to the server every 60 seconds
ssh_config is the system-wide configuration file for ssh. For per-user configuration, which allows for different settings for each host: $echo 'ServerAliveInterval 60' >> ~/.ssh/ssh_config On OSX: $echo 'ServerAliveInterval 60' >> ~/.ssh/config or $echo 'ServerAliveInterval 60' >> ~/etc/ssh_config

Adding a startup script to be run at bootup Ubuntu
This script will run each time you boot up.The script must be in /etc/init.d directory.

loop over a set of items that contain spaces
If you want to operate on a set of items in Bash, and at least one of them contains spaces, the `for` loop isn't going to work the way you might expect. For example, if the current dir has two files, named "file" and "file 2", this would loop 3 times (once each for "file", "file", and "2"): $ for ITEM in `ls`; do echo "$ITEM"; done Instead, use a while loop with `read`: $ ls | while read ITEM; do echo "$ITEM"; done

Get a shell with a not available account

Takes and displays screenshot of Android phone over adb.
Dependencies on phone: adb access, screencap command, base64 command. Dependencies on computer: adb, sed, base64, display (from imagemagick, but can substitute other image viewer which reads from stdin). This should work around adb stupidies (i.e. that it replaces \n with \r\n) with base64.

Simplest way to get size (in bytes) of a file


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