How to handle global variable inside recursive function? - bash

Question

I'm trying to traverse over directory and its subdirectories to extract files. The code below works fine, however, the global variable "DECOMPRESSED_FILES_COUNTER" is incremented only within the first directory.
Ignore the "IS_EXTRACTED" variable(this is for other use)
Here is a little part of my script:
FILE_OUTPUT_HIDE=/dev/null 2>&1
DECOMPRESSED_FILES_COUNTER=0
CURRENT_PATH=$(pwd)
function extractFiles(){
IS_EXTRACKED=""
if ( file "$FILE_I" | grep -w 'zip' >$FILE_OUTPUT_HIDE )
then
unzip -o $FILE_I >$FILE_OUTPUT_HIDE
let "DECOMPRESSED_FILES_COUNTER++"
elif ( file "$FILE_I" | grep -w 'gzip' >$FILE_OUTPUT_HIDE )
then
gunzip -k -f -N $FILE_I >$FILE_OUTPUT_HIDE
let "DECOMPRESSED_FILES_COUNTER++"
elif ( file "$FILE_I" | grep -w 'bzip2' >$FILE_OUTPUT_HIDE )
then
bzip2 -k -d -f $FILE_I >$FILE_OUTPUT_HIDE
let "DECOMPRESSED_FILES_COUNTER++"
else
IS_EXTRACKED=false
fi
}
function recursiveMode(){
for FILE_I in *; do
if [ -d "$FILE_I" ]; then
(cd -- "$FILE_I" && recursiveMode)
fi
extractFiles
done
}
Example:
omri#omri-pc:/mnt/c/users/omri/mission$ ./myScript -r newFolder
Assuming that "newFolder" had 3 archives files and in its subfolder "otherFolder" had 2 archives files.
I expect the DECOMPRESSED_FILES_COUNTER to be 5, but the actual value is 3 even though all files were extracted.

Answer 1

The subshell you use to localize the change in the directory causes changes to the variable to only persist in that subshell. Use pushd and popd instead to change and restore the working directory.
function recursiveMode(){
for FILE_I in *; do
if [ -d "$FILE_I" ]; then
pushd "$FILE_I"
recursiveMode
popd
fi
extractFiles
done
}
However, given the number of bash-only features you are using, you may as well use another one: the ** glob pattern to do the recursion for you.
shopt -s globstar
counter=0
extractFile () {
if file "$1" | grep -qw bzip2; then
bzip2 -k -d -f "$1"
elif file "$1" | grep -qw gzip; then
gunzip -k -f -N "$1"
elif file "$1" | grep -qw zip; then
unzip -o "$1"
else
return
fi > /dev/null
((counter++))
}
for f in **/*; do
extractFile "$f"
done