Commands by mohan43u (13)

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user 'tr' to convert mixed case in a file to lower case
convert mixed case in a file to lower case

List 10 largest directories in current directory
du -m option to not go across mounts (you usually want to run that command to find what to destroy in that partition) -a option to also list . files -k to display in kilobytes sort -n to sort in numerical order, biggest files last tail -10 to only display biggest 10

Matrix Style
Unlike other alternatives, this command only relies on bash builtins and should also work on windows platforms with the bash executable. Sparseness corresponds to the number 128 and can be adjusted. To print all possible digits instead of only 0 and 1 replace RANDOM%2 by RANDOM%10 or RANDOM%16 to add letters [A-F].

Remote screenshot
Say if you're logged into a remote system via ssh and this system has an x window system, but yet you still want a screen shot of what's going on graphically. This will do it for you. :-)

Use wget to download one page and all it's requisites for offline viewing

Access to specific man page section
You can view the man pages from section five by passing the section number as an argument to the man command

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"

git remove files which have been deleted
It deletes all removed files, updates what was modified, and adds new files.

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

Perform a branching conditional
This will perform one of two blocks of code, depending on the condition of the first. Essentially is a bash terniary operator. To tell if a machine is up: $ ping -c1 machine { echo succes;} || { echo failed; } Because of the bash { } block operators, you can have multiple commands $ ping -c1 machine && { echo success;log-timestamp.sh }|| { echo failed; email-admin.sh; } Tips: Remember, the { } operators are treated by bash as a reserved word: as such, they need a space on either side. If you have a command that can fail at the end of the true block, consider ending said block with 'false' to prevent accidental execution


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