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Lvextend logical volume
this command extends your logical volume. then it does a resize2fs on it as well. added the -r switch to make it launch resize.

A one-line web server in Ruby
Here's how to serve a directory in one line of Ruby. Handy for sharing files at a conference, for example.

bulk rename files with sed, one-liner
Far from my favorite, but works in sh and with an old sed that doesn't support '-E'

use google's text-to-speech and play in media player

Rename files in batch

Validating a file with checksum

Truncate long strings in columns and use custom header names
Using the --table-truncate ( -T ) option, you can specify the columns you will allow to be truncated. This helps when you have some columns that are unusually long, or a small terminal window. In this example we will print out the /etc/passwd file in columns. We are using a colon as our separator ( -s: ), defining that we want table output ( -t ), defining the column names ( -N ) and allowing the column NAME to be truncated ( -T ).

port scan using parallel
It takes over 5 seconds to scan a single port on a single host using nmap $ time (nmap -p 80 192.168.1.1 &> /dev/null) real 0m5.109s user 0m0.102s sys 0m0.004s It took netcat about 2.5 minutes to scan port 80 on the class C $ time (for NUM in {1..255} ; do nc -w 1 -z -v 192.168.1.${NUM} 80 ; done &> /dev/null) real 2m28.651s user 0m0.136s sys 0m0.341s Using parallel, I am able to scan port 80 on the entire class C in under 2 seconds $ time (seq 1 255 | parallel -j255 'nc -w 1 -z -v 192.168.1.{} 80' &> /dev/null) real 0m1.957s user 0m0.457s sys 0m0.994s

Get information about memory modules
To take information about the characteristics of the installed memory modules.

Get the IP address of a machine. Just the IP, no junk.
Why use many different utilities all piped together, when you only need two?


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