Commands by jaimerosario (12)

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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"

sed : using colons as separators instead of forward slashes
Having to escape forwardslashes when using sed can be a pain. However, it's possible to instead of using / as the separator to use : . I found this by trying to substitute $PWD into my pattern, like so $ sed "s/~.*/$PWD/" file.txt Of course, $PWD will expand to a character string that begins with a / , which will make sed spit out an error such as "sed: -e expression #1, char 8: unknown option to `s'". So simply changing it to $ sed "s:~.*:$PWD:" file.txt did the trick.

Find files that were modified by a given command
Traces the system calls of a program. See http://linuxhelp.blogspot.com/2006/05/strace-very-powerful-troubleshooting.html for more information.

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

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

small CPU benchmark with PI, bc and time.
$ # 4 cores with 2500 pi digits $ CPUBENCH 4 2500 $. $ every core will use 100% cpu and you can see how fast they calculate it. $ if you do 50000 digitits and more it can take hours or days

Copy a file using dc3dd and watch its progress (very nice alternative to dd)
Requires the dc3dd package - available at http://dc3dd.sourceforge.net

Grep recursively for a pattern and open all files that match, in order, in Vim, landing on 1st match

List alive hosts in specific subnet
Works on any machine with nmap installed. Previous version does not work on machines without "seq". Also works on subnets of any size.

Count the number of characters in each line


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