Merge multiple jpg into single pdf in Linux

Question

I used the following command to convert and merge all the jpg files in a directory to a single pdf file.

convert *.jpg file.pdf

The files in the directory are numbered from 1.jpg to 123.jpg. The conversion went fine but after converting the pages were all mixed up. I wanted the pdf to have pages from 1.jpg to 123.jpg in the same order as they are named. I tried with the following command as well:

cd 1 FILES=$( find . -type f -name "*jpg" | cut -d/ -f 2) mkdir temp && cd temp for file in $FILES; do BASE=$(echo $file | sed 's/.jpg//g'); convert ../$BASE.jpg $BASE.pdf; done && pdftk *pdf cat output ../1.pdf && cd .. rm -rf temp

But still no luck. Operating platform Linux. Any help will be appreciated!

 

Answer 1

The problem is because your shell is expanding the wildcard in purely alphabetical order, and because the lengths of the numbers are different, the order will be incorrect:

$ echo *.jpg 1.jpg 10.jpg 100.jpg 101.jpg 102.jpg ...

The solution is to pad the filenames with zeros as required so they're the same length before running your convert command:

$ for i in *.jpg; do num=`expr match "$i" '\([0-9]\+\).*'`; > padded=`printf "%03d" $num`; mv -v "$i" "${i/$num/$padded}"; done

Now the files will be matched by the wildcard in the correct order, ready for the convert command:

$ echo *.jpg 001.jpg 002.jpg 003.jpg 004.jpg 005.jpg 006.jpg 007.jpg 008.jpg ...