commandlinefu.com is the place to record those command-line gems that you return to again and again.
Delete that bloated snippets file you've been using and share your personal repository with the world. 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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Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
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Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:
when using Gnome or KDE, you will have a hard time getting a screenshot of something like a login screen, or any other screen that occurs before the desktop environment is up and monitoring the printscreen key. (this probably applies for other DEs as well, but I haven't used them)
What this command is meant to do is take a screenshot of an X window using a command you can run from your virtual terminals (actual text terminals, not just an emulator) To do this:
Press CTRL+ALT+F1 to go to a virtual (text) terminal once your login window comes up
Login to the virtual terminal and enter the command (you'll have to type it in)
You should now have a file called screenshot.png in your home directory with your screenshot in it.
For those of you who are new to the virtual terminal thing, you can use CTRL+ALT+F7 to get back to your regular GUI
Broaden your knowledge of the utilities available to you in no particular order whatsoever! Then use that knowledge to create more nifty one-liners that you can post here. =p
Takes a random number modulo the number of files in $dir, prints the filename corresponding to that number, and passes it as an argument to man.
This will allow you to convert an audio file to wav format, and send it via ssh to a player on the other computer, which will open and play it there. Of course, substitute your information for the sound file and remote address
You do not have to use paplay on the remote end, as it is a PulseAudio thing. If the remote end uses ALSA, you should use aplay instead. If it uses OSS, you should berate them about having a lousy sound system. Also, you're not limited to transmitting encoded as wav either, it's just that AFAIK, most systems don't come with mp3 codecs, but will play wav files fine.
If you know SoX is installed on the remote end and has mp3 codecs, you can use the following instead:
cat Klaxon.mp3 |ssh [email protected] play -t mp3 -
this will transmit as mp3. Again, use your specific information. if you're not playing mp3s, use another type with the -t option
This takes quite a while on my system. You may want to test it out with /bin first, or background it and keep working.
If you want to get rid of the "No manual entry for [whatever]" and just have the [whatever], use the following sed command after this one finishes.
sed -n 's/^No manual entry for \(.*\)/\1/p' nomanlist.txt
the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor.
In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount
If you're going to use od, here's how to suppress the labels at the beginning. Also, it doesn't output the \x, hence the sed command at the end. Remove it for space separated hex values instead
first off, if you just want a random UUID, here's the actual command to use:
Your chances of finding a duplicate after running this nonstop for a year are about the same as being hit by a meteorite before finishing this sentence
The reason for the command I have is that it's more provably unique than the one that uuidgen creates. uuidgen creates a random one by default, or an unencrypted one based on time and network address if you give it the -t option.
Mine uses the mac address of the ethernet interface, the process id of the caller, and the system time down to nanosecond resolution, which is provably unique over all computers past, present, and future, subject to collisions in the cryptographic hash used, and the uniqueness of your mac address.
Warning: feel free to experiment, but be warned that the stdin of the hash is binary data at that point, which may mess up your terminal if you don't pipe it into something. If it does mess up though, just type
Change the number to change the number of spaces. Leaving it out defaults to 8. Leaving out the filename defaults to stdin.
And to do it in reverse, you can use the unexpand command.
Same as another one I saw, just with a cleaner sed command
Edit: updated the sed command to use the [[:xdigit:]] character class - more portable between locales
Note that it will have a newline inserted after every 32 characters of input, due to the output of xxd