Testable and self-contained bash script

Question

I wrote a short bash script for a completion check of downloading images.

goal of this code (Added)

I have some downloading content directories. Each of them has a script for downloading images(tmp.sh), for example, the following one:

wget -nc \
 http://www.example.com/001.jpg \
 http://www.example.com/002.jpg \
 ...
 http://www.example.com/123.jpg \

I want to know which wget completes downloading all or failed.

If you have any good ideas, please tell me them. Thank you.

done.sh

#!/bin/sh
# if a directory name is assigned
if [ $# -eq 1 ]; then
 a=`ls -1 1ドル/*.jpg | wc -l`
 b=`grep jpg 1ドル/tmp.sh | wc -l`
 if [ $a = $b ]; then
 echo 1ドル
 fi
 exit
fi
# if some directory names are assigned
if [ $# -gt 1 ]; then
 for dir1 in "$@"; do
 ./done.sh $dir1
 done
fi
# if directory names are not assigned
if [ $# -eq 0 ]; then
 ls -d */ | xargs ./done.sh
fi
```

Answer 1

Good

• good indentation
• somewhat helpful comments
• good to do the ; then bit on the same line as the if

Suggestions

• use double brackets for conditionals
• try shellcheck (It will tell you to put quotes around your variable substitutions.)
• put your arguments into named variables so you don't keep have to referring to 1ドル
• put the 3 sections into if...elif...else structure to make clear that you're only going to go into one of them
• check for the existance of ./done.sh at the beginning
• explain what the goal of the script is somewhere.

• Haruo Wakakusa: Thanks for the great suggestions. I forgot the programming fundamental techniques in shell programming. I'll correct my code and paste it below the original code.
• mdfst13: @HaruoWakakusa You may want to read What I can and cannot do after receiving answers before you do that. As it is one of the things that you can't do under this site's rules.
• Haruo Wakakusa: Yes, I'll add only the purpose of this code.