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coloured shell prompt
This coloured prompt will show: username in green, grey "@" sign, hostname in red, current directory in yellow, typed commands in green.

prints line numbers

Log the current memory statistics frequently to syslog
Uses logger in a while loop to log memory statistics frequently into the local syslog server.

Create a backup of the file.
It will create a backup of the filename. The advantage is that if you list the folder the backups will be sorted by date. The command works on any unix in bash.

Efficiently extract lines between markers
GNU Sed can 'address' between two regex, but it continues parsing through to the end of the file. This slight alteration causes it to terminate reading the input file once the STOP match is made. In my example I have included an extra '/START/d' as my 'start' marker line contains the 'stop' string (I'm extracting data between 'resets' and using the time stamp as the 'start'). My previous coding using grep is slightly faster near the end of the file, but overall (extracting all the reset cycles in turn) the new SED method is quicker and a lot neater.

add static arp entry to default gateway, arp poison protection

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

Search manpages for a keyword
Search manpages for a keyword. Very useful when you don't know where to find the information.

Monitor connection statistics with netstat and watch

converting vertical line to horizontal line


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