Commands by Sepero (6)

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

Find pages returning 404 errors in apache logs
Finds the top ten pages returning an http response code of 404 in an apache log.

Simulate typing

Transforms a file to all uppercase.
Transforms a file to all uppercase.

How to extract 5000 records from each table in MySQL
How to extract data from one table: mysqldump --opt --where="true LIMIT 5000" dbinproduzione tabella > miodbditest_tabella.sql

Set laptop display brightness
Run as root. Path may vary depending on laptop model and video card (this was tested on an Acer laptop with ATI HD3200 video). $ cat /proc/acpi/video/VGA/LCD/brightness to discover the possible values for your display.

Create the signature base string required for a Twitter stream feed
This is the SECOND command in a set for five that are needed for a Twitter stream feed. This command creates variable "b", the so-called "base string" required for oauth in Twitter stream feed requests. (The 256 char limit prevents giving it a better name) We use five environment variables created by a previous step: id, k1, once, ts and k3. The five environment variables are created in a separate command, please see my other commands. For more information on the signature base string, see dev.twitter.com/apps, click on any app (or create a new one) and then go to the "OAuth Tool" tab.

slow down CPU and IO for process and its offsprings.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

pretend to be busy in office to enjoy a cup of coffee
This will turn it in an infinite loop and also shows random words from a file, so it won't be the same each time and also not just a number.

Setup a persistant SSH tunnel w/ pre-shared key authentication
This creates a persistent ssh -i /path/to/key -ND local-IP:PORT User@Server connection. You may have to install autossh. -f puts in daemon mode. if you are having trouble, try it without -f.


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: