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.
If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/
You can sign-in using OpenID credentials, or register a traditional username and password.
First-time OpenID users will be automatically assigned a username which can be changed after signing in.
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.
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:
In the vein of "can you do it better", here is my take on using "ping" to emulate sleep in a DOS/BAT script. If one can use ping at all then the multicast address will be valid but will not respond. By doing only one ping (-n 1) and setting a timeout in milliseconds (-w 10000) you have a fairly accurate timer. This example gives about a 10 second sleep.
the command will not include hidden files
Reduces the size of images.
Searches in order of the directories of $PATH. Stops after finding the entry; looks for only that fileName. Works in Bourne, Korn, Bash and Z shells.
You can replace "." with your folder
I liked vaporub's suggestion, here a little simplification of the sed command.
You can also specify width and height of the resized image (in pixels), as an alternative to using a percentage.
You can find every file with png extension and redirect its output to file. Later you can find a string inside the file.
preserve all except context and xattr. useful when moving a running system to a new partition.
Based on the execute with timeout command in this site.
A more complex script:
# This script will check the avaliability of a list of NFS mount point,
# forcing a remount of those that do not respond in 5 seconds.
# It basically does this:
# NFSPATH=/mountpoint TIMEOUT=5; perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $NFSPATH" || (umount -fl $NFSPATH; mount $NFSPATH)
for i in $@; do
echo "Checking $i..."
if ! perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $i" > /dev/null 2>&1; then
echo "$SCRIPT_NAME: $i is failing with retcode $?."1>&2
echo "$SCRIPT_NAME: Submmiting umount -fl $i" 1>&2
umount -fl $i;
echo "$SCRIPT_NAME: Submmiting mount $i" 1>&2
This helps quickly get information for each disk that is seemingly having hardware issues.
release upgrades are major upgrades as from 8.04 to 8.10 or from 8.10 to 9.04
update-manager-core must be installed:
sudo apt-get install update-manager-core
in some cases you must edit '/etc/update-manager/release-upgrades' and set 'Prompt=normal'
You WILL have problems if the files have the same name.
Use cases: consolidate music library and unify photos (especially if your camera separates images by dates).
After running the command and verifying if there was no name issues, you can use
ls -d */ | sed -e 's/^/\"/g' -e 's/$/\"/g' | xargs rm -r
to remove now empty subdirectories.
Us dc instead of bc. RPN FTW!!!
These should be a little faster since they don't have to spawn grep.
use this command to gzip the file and write to stdout and from the stdout redirect to the another file
The thunderbird message datastores get corrupt some times causing random failures, compaction to fail and general suck in thunderbird. Removing them causes thunderbird to rebuild the indexes and makes things quick again.