Commands by unixx (2)

What's this?

commandlinefu.com 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.

Share Your Commands


Check These Out

pngcrush all .png files in the directory
Nothing too magical here, just uses pngcrush to losslessly compress all your pngs!

Echo the latest commands from commandlinefu on the console
A Quick variation to the latest commands list with the new-lines skipped. This is faster to read.

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

Compress files found with find
tar options may change ;) c to compress into a tar file, z for gzip (j for bzip) man tar -print0 and -0t are usefull for names with spaces, \, etc.

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Turn off your laptop screen on command
echo 'alias monitor_off="sleep 1; xset dpms force standby"' >> ~/.bash_aliases ; . ~/.bash_aliases # now monitor_off does what you think

Backticks are evil
This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes: $ program1 $(program2 $(program3 $(program4))) versus $ program1 `program2 \`program3 \`program4\`\`` Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.

concatenate compressed and uncompressed logs
with zcat force option it's even simpler.

Battery real life energy vs predicted remaining plotted
This time I added a print to reemaining energy, every minute, time stamped. The example shown here is complete and point to large discrepancies as time passes, converging to accuracy near the end.

Print out your hard drive to a jet-direct compatible printer.
Where 192.168.1.2 is a printer with jet-direct. No, I don't suggest this as a backup method.


Stay in the loop…

Follow the Tweets.

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.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: