Commands by weapstyle (1)

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

Quickly batch resize images
-geometry (preserves values of height and width given, and aspect ratio). WARNING: While 'resize' creates resized copies of original files, 'mogrify' works on the original files, replacing them. It will overwrite the source files, use with caution, and backup regularly.

Convert ascii string to hex
Here's a version that uses perl. If you'd like a trailing newline: $ perl -pe 's/(.)/sprintf("\\x%x", ord($1))/eg; END {print "\n"}'

Display / view the contents of the manifest within a Java jar file
Displays the manifest within a jar file. Can use it to confirm version number, etc.

Partition a sequence of disk drives for LVM with fdisk
So, I'm using a CentOS VM in VirtualBox, and created four new disks in the SCSI controller. The VM created the folders: /dev/sda /dev/sdb /dev/sdc /dev/sdd Using a 'for loop' all disks are partitioned for LVM.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Quickly build ulimit command from current values
It is helpful to know the current limits placed on your account, and using this shortcut is a quick way to figuring out which values to change for optimization or security. Alias is: $ alias ulimith="command ulimit -a|sed 's/^.*\([a-z]\))\(.*\)$/-\1\2/;s/^/ulimit /'|tr '\n' ' ';echo" Here's the result of this command: $ ulimit -c 0 -d unlimited -e 0 -f unlimited -i 155648 -l 32 -m unlimited -n 8192 -p 8 -q 819200 -r 0 -s 10240 -t unlimited -u unlimited -v unlimited -x unlimited $ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 155648 max locked memory (kbytes, -l) 32 max memory size (kbytes, -m) unlimited open files (-n) 8192 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) unlimited virtual memory (kbytes, -v) unlimited file locks (-x) unlimited

OpenSSL one line CSR & Key generation

strip config files of comments
some configuration files, particularly those installed by default as part of a package, have tons of comment lines, to help you know what's possible to configure, and what it means. That's nice, but sometimes you just want to see what specifically what _has_ been configured. That's when I use the above snippet, which I save as a bash alias 'nocom' (for 'no comments'). Apache default config files are perfect examples of when/why this script is handy.

Find all files currently open in Vim and/or gVim
Catches .swp, .swo, .swn, etc. If you have access to lsof, it'll give you more compressed output and show you the associated terminals (e.g., pts/5, which you could then use 'w' to figure out where it's originating from): lsof | grep '\.sw.$' If you have swp files turned off, you can do something like: ps x | grep '[g,v]im', but it won't tell you about files open in buffers, via :e [file].

open two files on top of each other in vim (one window, two panes)


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: