topic Re: Changing a filename to a regex pattern in a shell script in Operating System - Linux

Changing a filename to a regex pattern in a shell script

Jonas Kvinge — Tue, 05 Sep 2006 15:50:27 GMT

I have a image gallery where files are named in the format img_yyyymmdd_nnn_widthxheight.jpg, for example: img_19981117_001_320x240.jpg

I've written a script that creates a list of all the images in a file. But I need to replace the filename of the image with a regex pattern so it applies to same image with a diffrent size. (Since different sizes of the image have different filename).

How can I replace the image filename (img_19981117_001_320x240.jpg) with a regex pattern of the filename like: /^img_19981117_001_[0-9]*x[0-9]*\.jpg$/ using sed or awk?

#!/bin/sh

DIR="$1"

if [ "$DIR" = "" ] ; then
echo "ERROR: You need to specify dir."
exit -1;
fi

for a in `ls $DIR`
do
if [ ! -f "${DIR}/${a}/IMAGEDESC" ] ; then
echo "Creating IMAGEDESC in ${DIR}/${a}";
for b in `ls $DIR/$a/thumb`
do
echo "/${b}/ No Description" >> "${DIR}/${a}/IMAGEDESC"
done;
fi
done;

exit 0;

Re: Changing a filename to a regex pattern in a shell script

James R. Ferguson — Tue, 05 Sep 2006 16:23:28 GMT

Hi Jonas:

Do you mean that you have a file that looks something like:

img_19981117_001_320x240.jpg
img_20001117abcd_320x240.jpg
img_20001117efgh_640x1400.jpg

...and you want:

img_19981117_001_[0-9]*x[0-9]*.jpg
img_20001117abcd_[0-9]*x[0-9]*.jpg
img_20001117efgh_[0-9]*x[0-9]*.jpg

...if so:

# perl -ple 's%(.+_)(\d+)x(\d+)\.jpg%$1\[0-9]*x\[0-9]*.jpg%' file

Regards!

...JRF...

Re: Changing a filename to a regex pattern in a shell script

Sandman! — Tue, 05 Sep 2006 17:15:57 GMT

How about a sed construct in your for loop:

for a in `ls $DIR`
do
echo $a | sed -n '/^img_19981117_001_[0-9]*x[0-9]*\.jpg$/p'
done

Re: Changing a filename to a regex pattern in a shell script

Ninad_1 — Tue, 05 Sep 2006 23:38:01 GMT

Jonas,

If I have understood your problem correctly
i.e. you have filename with a particular image resolution and now you want to create a list of files by listing the existing files and renaming the img_yyyymmdd_nnn_widthxheight.jpg file with img_yyyymmdd_nnn_newwidthxnewheight.jpg then here is the solution.
Assuming that the b variable is the filename of the format img_yyyymmdd_nnn_widthxheight.jpg in the listing from the $DIR/$a/thumb
You can define newwidth and newheight as variable and define a value or hardcode the values.

#!/bin/sh

DIR="$1"

if [ "$DIR" = "" ] ; then
echo "ERROR: You need to specify dir."
exit -1;
fi
newwidth=640 # define a value for newwidth
newheight=800 # define a value for newheight

for a in `ls $DIR`
do
if [ ! -f "${DIR}/${a}/IMAGEDESC" ] ; then
echo "Creating IMAGEDESC in ${DIR}/${a}";
for b in `ls $DIR/$a/thumb`
do
echo "${b%_*.jpg}_${newwidth}x${newheight}.jpg"" >> "${DIR}/${a}/IMAGEDESC" # If you use the values thru newwidth and newheight variables
# echo "${b%_*.jpg}_640x800.jpg"" >> "${DIR}/${a}/IMAGEDESC" # If you want to directly specify the new resolution. Remove the # at the beginning and hash the above line
done;
fi
done;

exit 0;

Regards,
Ninad

Re: Changing a filename to a regex pattern in a shell script

Ninad_1 — Wed, 06 Sep 2006 01:34:01 GMT

Hi,

On observing my above post carefully - I have put an extra " for the echo "${b%_ .... statement after .jpg (.jpg"" should be corrected to .jpg" ). Please remove the same before execution.

So the lines should be
echo "${b%_*.jpg}_${newwidth}x${newheight}.jpg" >> "${DIR}/${a}/IMAGEDESC" # If you use the values thru newwidth and newheight variables
# echo "${b%_*.jpg}_640x800.jpg" >> "${DIR}/${a}/IMAGEDESC" # If you want to directly specify the new resolution. Remove the # at the beginning and hash the above line

Regards,
Ninad

Re: Changing a filename to a regex pattern in a shell script

Peter Nikitka — Thu, 07 Sep 2006 11:11:03 GMT

Hi,

I would try to split your filename using shell builtin string operators:
img=img_19981117_001_320x240.jpg
img_ident=${img%_*}
img_res=${img##*_}
print $img_ident
img_19981117_001
print $img_res
320x240.jpg

Now catenate your new filenames, e.g.:

touch img_19981117_001_320x240.jpg img_19981117_001_640x480.jpg
ls ${img_ident}_*.jpg
img_19981117_001_320x240.jpg img_19981117_001_640x480.jpg

or
low=320x240
med=640x480
hi=1280=960
img_medium=${img_ident}_$med.jpg

mfG Peter

Re: Changing a filename to a regex pattern in a shell script

Jonas Kvinge — Sun, 19 Nov 2006 14:32:32 GMT

James,

Thank you. You were the only one who gave a solution that worked.

Thanks to everyone else who tried to help me out.

My final script (mkgallery.sh) can be found in my photogallery package found on http://www.night-light.net/photogallery/ released under GPL.

Re: Changing a filename to a regex pattern in a shell script

Peter Nikitka — Sun, 19 Nov 2006 15:28:38 GMT

Oh fine - zero points, how generous!

Re: Changing a filename to a regex pattern in a shell script

Jonas Kvinge — Sun, 19 Nov 2006 16:23:09 GMT

Peter,

I really appreciate your time involved trying to help me out. You misunderstood my question, perhaps I explained it bad but you solution was no use to me, perhaps I should still give you a few points since because of your attempt, I don't know how the points thing work since I'm new to the forum. Sorry for any inconvenience caused. I will give you 2 points on your last reply. I hope this doesn't stop you from answering any further questions I might have.