Help:Command line image processing with ImageMagick

Create GIF animation from multiple files (myfile01.jpg, myfile02.jpg, ...) on the fly with Linux

Suppose you have several files (myfile01.jpg, myfile02.jpg, ...) and you want them converted into a file “animation.gif”. The following script will do it on the fly using convert (ImageMagick):

1 echo   myfile*.jpg | \
2   sed '1 s/^/echo "Start "`date`"..." \&\& convert /
3          s/$/ \\/
4        $ s/\\$/animation.gif \&\&  echo "Done  "`date`/' \
5 | sh

The trick behind this is to put things together by the “|” character (piping). The “\”-character continues the shell-command when there are line breaks and “&&” joins shell commands together. Explanations for each line in the script:

1. gets all files (file01.jpg, file02.jpg, ...). To get those numbered files see man rename.
2. sed composes and extends the piped echo. Prepend at the sed-address “the very first line” (1 s/../../) and do a regular expression replace by «s/search/replace/». So «1 s/^/.../» puts something at the 1st line but at the beginning of this line (^) and prepends therefore «echo "Start "`date`"..." && convert »
3. at each single line end ($) put a “ \”-character to get multi line echoed files into one single command
4. append at the sed-address “the very last line” ($ s/../../), search here for “\”-at the very end of the current line ($) and replace it by «animation.gif && echo "Done "`date`»
5. pipe all this together to the shell, which may something like:

echo "Start "`date`"..." && convert myfile01.jpg myfile02.jpg myfile03.jpg test.gif &&  echo "Done  "`date`

BTW: You can test the echoed command first by deleting the last pipe “| sh”.

Usually you can do the same by just typing:

convert myfile*.jpg animation.gif

...but if files have different dates or if they where saved at different times, this can cause a distorted animation. So the safe way is to explicitly let convert use only the provided file order.