BASH - look for file in for loop issue - bash

Question

So the issue is the following:
I have a folder with 4 .zip's and .md5's for all of them with the same base filename.
I have a FOR loop:
for S in *.zip;
do
{
check_md5
}
done
check_md5 ()
{
if md5sum -c ${S:0:-4}.md5;
then
unzip_file
else
echo "MD5 failed"
fi
}
The problem: the script for the first zip runs fine, but when the unzip_file process ends it doesn't update the S variable to the next zip's filename.
During the unzip_file process it moves out of the original folder and at the end of it moves both the current 'S' .zip and .md5 to a archive folder.
Is it possible that the bug happens, because the unzip_file script moves out of the original folder or because it moves the first .zip and .md5 out of the original folder before it jumps to the next cycle?
Any other ideas?
Thanks in advance.

Answer 1

The problem is at the end of the first iteration you end up in a different directory. Following is one possible fix.
CWD="$PWD" # remember current working directory path
for S in *.zip; do
check_md5
cd "$CWD" # come back to the initial working directory at the end of each iteration
done
Though not related to the question, I would prefer passing the file name to the function instead of accessing a variable set somewhere else. I find it hard to troubleshoot and more error prone.
unzip_file()
{
echo "unzipping $1"
# ...
}
check_md5()
{
if md5sum -c "${1:0:-4}.md5"; then
unzip_file "$1" # pass the argument forward
else
echo "MD5 failed"
fi
}
CWD="$PWD" # remember current working directory path
for S in *.zip; do
check_md5 "$S" # pass file name as an argument
cd "$CWD" # come back to the initial working directory
done
As another note, your function naming/modularization doe not look good. e.g. check_md5 does a lot more than just checking md5 sum.