Commands by prasad (3)

What's this? is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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from the console, start a second X server
This starts a very basic X session, with just a simple xterm. You can use this xterm to launch your preferred distant session. $ ssh -X [email protected] gnome-session Try also startkde or fluxbox or xfce4-session. To switch between your two X servers, use CTRL+ALT+F7 and CTRL+ALT+F8.

geoip information
Not my script. Belongs to mathewbauer. Used without his permission. This script gives a single line as shown in the sample output. NOTE: I have blanked out the IP address for obvious security reasons. But you will get whatever is your IP if you run the script. Tested working in bash.

Dump a configuration file without comments or whitespace...
A short, *easy-er* to remember command for stripping whitespace and comments from a config file, (or any file for that matter). Remember regex as: slash, space, star. pound, slash, bar. pointy-hat, dollar. (or "caret, dollar" if you must) :-P

Draw a Sierpinski triangle
OK, not the most useful but a good way to impress friends. Requires the "display" command from ImageMagick.

Find files and list them sorted by modification time
This uses the ability of find (at least the one from GNU findutils that is shiped with most linux distros) to display change time as part of its output. No xargs needed.

View acceptable client certificate CA names asked for during SSL renegotiations
The key is to use the -prexit option at the command line, and then type "quit" instead of CTRL-C to exit OpenSSL. OpenSSL will then dump its last negotiated state, printing out the contents of the renegotiated handshake. Crucial for debugging client certificate configurations on web servers such as IIS, which renegotiate the SSL/TLS connection with the HTTP request in-flight to ask the client for a cert.

Capture SMTP / POP3 Email

Watch the disk fill up
While copying a large file that may take up a good chunk of your hard drive, start the copy and run this command concurrently. It will print out the disk information every second. It's pretty handy when you have a large copy with nothing to monitor the progress.

a function to find the fastest DNS server gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.

Wait for an already launched program to stop before starting a new command.
Referring to the original post, if you are using $! then that means the process is a child of the current shell, so you can just use `wait $!`. If you are trying to wait for a process created outside of the current shell, then the loop on `kill -0 $PID` is good; although, you can't get the exit status of the process.

Stay in the loop…

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