I have file names (from image tiles) consisting of two numbers separated by an underscore, e.g.
142_27.jpg
7_39.jpg
1_120.jpg
How can I (in linux) add leading zeros to both of these numbers? What I want is the file names as
142_027.jpg
007_039.jpg
001_120.jpg
You can use a single awk command to format filenames with leading zeroes using a printf:
for f in *.jpg; do
echo mv "$f" $(awk -F '[_.]' '{printf "%03d_%03d.%s", $1, $2, $3}' <<< "$f")
done
This will output:
mv 142_27.jpg 142_027.jpg
mv 1_120.jpg 001_120.jpg
mv 7_39.jpg 007_039.jpg
Once you're satisfied with the output, remove echo before mv command.
With perl based rename command
$ touch 142_27.jpg 7_39.jpg 1_120.jpg
$ rename -n 's/\d+/sprintf "%03d", $&/ge' *.jpg
rename(1_120.jpg, 001_120.jpg)
rename(142_27.jpg, 142_027.jpg)
rename(7_39.jpg, 007_039.jpg)
The -n option is for dry run, remove it for actual renaming
If perl based rename command is not available:
$ for f in *.jpg; do echo mv "$f" "$(echo "$f" | perl -pe 's/\d+/sprintf "%03d", $&/ge')"; done
mv 1_120.jpg 001_120.jpg
mv 142_27.jpg 142_027.jpg
mv 7_39.jpg 007_039.jpg
Change echo mv to just mv once dry run seems okay
You can do it with a little shell-script using sed:
for i in *.jpg;
do
new=`echo "$i" | sed -n -e '{ s/^\([0-9]\{0,3\}\)_\([0-9]\{0,3\}\).jpg/000\1_000\2.jpg/ };
{s/\([0-9]*\)\([0-9]\{3\}\)_\([0-9]*\)\([0-9]\{3\}\).jpg/\2_\4.jpg/p };'`;
mv "$i" "$new";
done;
I first append three leading zeros at the said places by default and afterwards cut off as many digits as necessary brginning at the start at said places so that only 3 digits are left
with bash substitution(a,b)
windows(bash)
for f in *.jpg;do a=${f%_*};b=${f#*_};mv $f $(printf "%03d_%07s" $a $b);done
linux
for f in *.jpg;do a=${f%_*};b=${f#*_};b=${b%.*};mv $f $(printf "%03d_%03d".jpg $a $b);done
