Commands by dendoes (4)

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VIM version 7: edit in tabs
Edit the files, each in a separate tab. use gT and gt to move to the left- and right-tab, respectively. to add another tab while editing, type ':tabe filename'

generate 30 x 30 matrix
Replaces hexdump with the more succint xxd, and the sed was unnecessarily complex.

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"

View user activity per directory.
View all files opened by a user in specified directory. The +D option makes lsof search all sub-directories to complete depth, while ignoring symbolic links.

Inverted cowsay
It's quite fun to invert text using "flip.pl" (ref: http://ubuntuforums.org/showthread.php?t=2078323 ). Slightly more challenging is to flip a whole "cowsay". :-)

Find common lines between two files

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

Rapidly invoke an editor to write a long, complex, or tricky command
Allows you to edit your command using your chosen editor. Works in bash with "set -o vi".

move you up one directory quickly
Alias a single character 'b' to move to parent directory. Put it into your .bashrc or .profile file. Using "cd .." is one of the most repetitive sequence of characters you'll in the command line. Bring it down to two keys 'b' and 'enter'. It stands for "back" Also useful to have multiple: alias b='cd ../' alias bb='cd ../../' alias bbb='cd ../../../' alias bbbb='cd ../../../../'

total percentage of memory use for all processes with a given name
This command will add up RAM usage of all processes whose name contains "java" and output the sum of percentages in HRF. Also, unlike the original #15430, it wont fail on processes with a usage of >9.9%. Pleases note that this command wont work reliably in use cases where a significant portion of processes involved are using less than 0.1% of RAM, because they will be counted as "0", even though a great number of them could add up to significant amounts.


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