Batch Script to Convert PNG to XPM

[jadube]

I can use the convert command to convert a single image from PNG to XPM, but cannot get (my first) script to work. I want it to convert a directory of PNGs to XPM. Any advice appreciated. Thank you!

echo "Script Starting.."
cd /home/user/Pictures/icons
echo "start For loop"
for pic in 'ls *.png'
do
	echo "converting $pic"
	convert $pic $pic.xpm
done
echo "finished"

------------------------------------
While looking for info I came across a 2nd script which might work if modified - this is fyi. Source: Imagemageic.org

  # Use a simple shell loop, to process each of the images.
  mkdir thumbnails
  for $f in *.jpg
  do   convert $f -thumbnail 200x90 thumbnails/$f.gif
  done
  # Use find to substitute filenames into a 'convert' command
  # This also provides the ability to recurse though directories by removing
  # the -prune option, as well as doing other file checks (like image type,
  # or the disk space used by an image).
  find * -prune -name '*.jpg' \
         -exec  convert '{}' -thumbnail 200x90 thumbnails/'{}'.gif \;
  # Use xargs -- with a shell wrapper to put the argument into a variable
  # This can be combined with either "find" or "ls" to list filenames.
  ls *.jpg | xargs -n1 sh -c 'convert $0 -thumbnail 200x90 thumbnails/$0.gif'
  # An alternative method on linux (rather than plain unix)
  # This does not need a shell to handle the argument.
  ls *.jpg | xargs  -I FILE   convert FILE -thumbnail 200x90 th_FILE.gif

[wje_lf]

You would have gotten farther with:

echo "Script Starting.."
cd /home/user/Pictures/icons
echo "start For loop"
for pic in `ls *.png`
do
	echo "converting $pic"
	convert $pic $pic.xpm
done
echo "finished"

Do you see what I did there? Those two characters in red, which were single quotes in your code, have been converted to backticks. That's on the same key on the standard computer keyboard as the tilde ~ is, in the upper left corner.

But I'd recommend that you make the difference more obvious, by doing this instead:

echo "Script Starting.."
cd /home/user/Pictures/icons
echo "start For loop"
for pic in $(ls *.png)
do
	echo "converting $pic"
	convert $pic $pic.xpm
done
echo "finished"

That should fix things. But there will be one minor flaw. File aaa.png will be converted, for example, and the name of the new file will be aaa.png.xpm. I am guessing that you want, instead, aaa.xpm. If that is the case, do this instead:

echo "Script Starting.."
cd /home/user/Pictures/icons
echo "start For loop"
for pic in $(ls *.png)
do
	echo "converting $pic"
	convert $pic $(basename $pic.xpm .xpm)
done
echo "finished"

Hope this helps.

[jadube]

Bill, Thank you. I never would have understood the tick mark (vs) quote problem. The script runs and I get the "converting pic" messages as each file is processed. But I never find the output/xpm files. The script pemission is 755, and I have run it as root and user. But still no files. I'm re-reading documentation on permissions (I figure that is the problem) but if you suspect another problem please let me know. Thanks again.

[i92guboj]

There's no point in doing this:

for i in $(ls *.png)

When this suffices:

for i in *.png

Parsing the output of ls will screw you up if the file names contain spaces and can lead to some other potential problems.

[wje_lf]

i92guboj has a point. Also, I had an error in the script I wrote. His change is in green, and mine is in red:

echo "Script Starting.."
cd /home/user/Pictures/icons
echo "start For loop"
for pic in *.png
do
        echo "converting $pic"
        convert $pic $(basename $pic .png).xpm
done
echo "finished"

[MoldyMagnet]

bash substitution FTW (see 'man bash' line 1238 or so):

for pic in *.png
do
	convert $pic ${pic/.xpm/.jpg}
done