Hide

What's this?

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/

Get involved!

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.

Hide

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:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Commands tagged Image processing from sorted by
Terminal - Commands tagged Image processing - 16 results
for I in *.CR2; do if [ `exiv2 pr -p a -u $I | grep 'xmp.Rating' | awk '{ print $4 }'` == "1" ]; then echo $I; fi; done
for i in {1..100}; do convert -background lightblue -fill blue -size 100x100 -pointsize 24 -gravity center label:$i $i.jpg; done
for i in *; do identify $i | awk '{split($3,a,"x"); if (a[2]>a[1]) print $1;}'; done
2014-05-27 23:41:24
User: dmmst19
Functions: awk
6

Most people take photos in landscape orientation (wider than it is tall). Sometimes though you turn the camera sideways to capture a narrow/tall subject. Assuming you then manually rotate those picture files 90 degrees for proper viewing on screen or photo frame, you now have a mix of orientations in your photos directory.

This command will print out the names of all the photos in the current directory whose vertical resolution is larger than its horizontal resolution (i.e. portrait orientation). You can then take that list of files and deal with them however you need to, like re-rotating back to landscape for consistent printing with all the others.

This command requires the "identify" command from the ImageMagick command-line image manipulation suite. Sample output from identify:

identify PICT2821.JPG

PICT2821.JPG JPEG 1536x2048 1536x2048+0+0 8-bit DirectClass 688KB 0.016u 0:00.006

find . -iname '*jpg' -print0 | xargs -0 exiftool -warning; find . -iname '*jpg' -print0 | xargs -0 jpeginfo -c
2013-01-28 16:44:19
Functions: find xargs
0

This checks jpeg data and metadata, should be grepped as needed, maybe a -B1 Warning for the first, and a -E "WARNING|ERROR" for the second part....

convert /home/user/file.jpg -resize 800x533 -strip -quality 80 -interlace line /home/user/web_file.jpg
jhead -autorot *
0

Digital cameras embed EXIF data into the images they create indicating which orientation the photo was taken in. Some viewers and editors are smart enough to read this, but many are not (and web browsers ignore it). jhead is one of not many tools available that can losslessly rotate jpeg images. This command reads the EXIF orientation of each image, and rotates it if necessary.

convert -density 300x300 input.pdf output.png
2011-01-28 00:36:31
2

If you skip this part:

-density 300x300

you'll get a very lo-res image.

for a in `ls`; do echo $a && convert $a -resize <Width>x<Height> $a; done
2009-08-02 22:35:24
User: leavittx
Functions: echo
0

Resizes all images in the curent directory to x resolution.

It is better than `mogrify -resize *.jpg` because of independence from extension of image (e.g. .jpg and .JPG) (:

find . -name "*jpg" -exec jpeginfo -c {} \; | grep -E "WARNING|ERROR"
2009-06-03 22:08:48
User: vincentp
Functions: find grep
11

Finds all corrupted jpeg files in current directory and its subdirectories. Displays the error or warning found.

The jpeginfo is part of the jpeginfo package in debian.

Should you wish to only get corrupted filenames, use cut to extract them :

find ./ -name *jpg -exec jpeginfo -c {} \; | grep -E "WARNING|ERROR" | cut -d " " -f 1
for i in *jpg; do jpeginfo -c $i | grep -E "WARNING|ERROR" | cut -d " " -f 1 | xargs -I '{}' find /mnt/sourcerep -name {} -type f -print0 | xargs -0 -I '{}' cp -f {} ./ ; done
2009-05-07 00:30:36
User: vincentp
Functions: cp cut find grep xargs
0

Find all corrupted jpeg in the current directory, find a file with the same name in a source directory hierarchy and copy it over the corrupted jpeg file.

Convenient to run on a large bunch of jpeg files copied from an unsure medium.

Needs the jpeginfo tool, found in the jpeginfo package (on debian at least).

convert {$file_in} \( +clone -background black -shadow 60x5+10+10 \) +swap -background none -layers merge +repage {$file_out}
2009-05-06 10:19:39
User: kureikain
Functions: merge
7

Please take notice that if you are going to use an JPG file for shadow effect,

let change -background none to -background white!

Because -background none make a transparent effect while JPG doesn't support transparent! And when viewing, you will get a bacl box!

So we will use an white background under! We can use other color as well!

convert -rotate $rotate -scale $Widthx$Height -modulate $brightness -contrast $contrast -colorize $red%,$green%,$blue% $filter file_in.png file_out.png
2009-05-06 10:14:22
User: kureikain
4
rotate: the rotate angle width, $height: width and height to scale to birghtness: change brighness
identify -ping imageName.png
identify -format "%wx%h" /path/to/image.jpg
mogrify -resize 1024 *.jpg
2009-02-11 00:01:29
User: mitzip
1

This command requires the imagemagick libraries and will resize all files with the .jpg extension to a width of 1024 pixels and will keep the same proportions as the original image.