Commands by thelaser (1)

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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"

Check whether laptop is running on battery or cable
If you want to do the same in OS X... grep as necessary for information you need....

command line calculator
simple function , floating point number is supported.

sort the contents of a text file in place.
sorts the contents of a file without the need for a second file to take the sorted output. This was previously entered as `sort -g list.txt -o $_` but as others have pointed out the $_ references the previous command. so this would've worked had that been the second part of a command joined with && like: cat list.txt && sort -g list.txt -o $_ The user below me Robin had the most correct command.

The proper way to read kernel messages in realtime.

List only the directories
-d: list directory entries instead of contents, and do not dereference symbolic links

quickly formats a fat partition. usefull for flash drives

diff will usually only take one file from STDIN. This is a method to take the result of two streams and compare with diff. The example I use to compare two iTunes libraries but it is generally applicable.
diff is designed to compare two files. You can also compare directories. In this form, bash uses 'process substitution' in place of a file as an input to diff. Each input to diff can be filtered as you choose. I use find and egrep to select the files to compare.

Generate random valid mac addresses
Python Alternative

Retrieve the size of a file on a server
Downloads the entire file, but http servers don't always provide the optional 'Content-Length:' header, and ftp/gopher/dict/etc servers don't provide a filesize header at all.


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