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Check if a machine is online
PING parameters c 1 limits to 1 pinging attempt q makes the command quiet (or silent mode) /dev/null 2>&1 is to remove the display && echo ONLINE is executed if previous command is successful (return value 0) || echo OFFLINE is executed otherwise (return value of 1 if unreachable or 2 if you're offline yourself). I personally use this command as an alias with a predefined machine name but there are at least 2 improvements that may be done. Asking for the machine name or IP Escaping the output so that it displays ONLINE in green and OFFLINE in red (for instance).

Get http headers for an url

backup all your commandlinefu.com favourites to a plaintext file
Usage: clfavs username password num_favourite_commands file_in_which_to_backup

convert chinese character into wubi86 input code
This CLI requiere the uniconv package that is provided with the yudit unicode editor . The wubi86 is a way to type chinese far quicker than pinyin . More infor on wikipedia : http://en.wikipedia.org/wiki/Wubizixing , http://www.yale.edu/chinesemac/wubi/xing.html

Title Case Files
All words of the filenames except "a", "of", "that" and "to" are capitalized. To also match words which begin with a specific string, you can use this: $ rename 's/\b((?!hello\b|t)[a-z]+)/\u$1/g' * This will capitalize all words except "hello" and words beginning with "t".

a function to find the fastest free DNS server
Evoke from the command like as: $ timeDNS commandlinefu.com . This isn't too terribly practical, but it is a good code example of using subshells to run the queries in parallel and the use of an "anonymous function" (a/k/a "inline group") to group i/o. . I'm assuming you have already defined your local DNS cache as ${local_DNS}, (here, it's 192.168.0.1). . You do need to install `moreutils` to get `sponge`. . If you're willing to wait, a slower version w/o sponge, (and w/o sorting), is this: . DNS () { for x in "192.168.0.1" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do (echo -n "$x "; dig @"$x" "$*"|grep Query) ; done ; }

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Uniquely (sort of) color text so you can see changes
Colorify colors input by converting the text to a number and then performing modulo 7 on it. This resulting number is used as the color escape code. This can be used to color the results of commands with complex outputs (like "482279054165371") so if any of the digits change, there's a good chance the color will change too. I say good chance because there's only 7 unique colors here, so assuming you were watching random numbers, there would be a 6/7 chance that the color would change when the number changed. This should really only be used to help quickly identify when things change, but should not be the only thing relied upon to positively assert that an output has not changed.

Execute a command before display the bash prompt
For example, if you are the type who type ls very often, then $ PROMPT_COMMAND=ls will ls after every command you issue.

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"


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