basename command not working as expected
The basename command has two uses, stripping path prefixes and (optionally) stripping suffixes.
To strip a path prefix, you can simply pass it a path, for example
basename /path/to/file.ext# file.extTo additionally strip a suffix, you need to tell basename the suffix you wish to strip, for example
basename /path/to/file.ext .ext# filebasename DSCN2612.JPG .JPG# DSCN2612So, basename won't "auto-detect" a suffix because in unix, files don't necessarily have suffixes. In other words, letters after a period aren't necessarily suffixes, so you need to explicitly tell it what suffix to strip.
There are some bash-specific alternatives to "auto-detect" and strip, however. For example,
x="file.ext"echo ${x%.*}# fileWithout knowing more, I might write your script as
for jpg in *.JPG; do base=${jpg%.*} convert "$jpg" "$base.pdf"done