Losing value of variables when exiting while-loop in bash

Question

In my script I want to count how many directories and files I have inside different directories. Inside "assignments" I have a lot of directories named "repo1", "repo2" etc. Here is my code:

ls -1 assignments | while read -r repoDir
do
    find assignments/"$repoDir" | grep -v .git | grep "$repoDir"/ | while read -r aPathOfRepoDir
    do
        BASENAME=`basename "$aPathOfRepoDir"`
        if [[ -d "$aPathOfRepoDir" ]]; then
            totalDirectories=$((totalDirectories+1))
        elif [[ -f "$aPathOfRepoDir" ]] && [[ "$BASENAME" == *".txt" ]]; then
            totalTextFiles=$((totalTextFiles+1))
        else
            totalOtherFiles=$((totalOtherFiles+1))
        fi
    done
    echo "total directories: $totalDirectories"
    echo "total text files: $totalTextFiles"
    echo "total other files: $totalOtherFiles"
    totalDirectories=0
    totalTextFiles=0
    totalOtherFiles=0;
done

When the while-loop is finished I lose the values of those 3 variables. I know that this is happening because the while-loop is a sub-shell but I don't know how can I somehow "store" the values of the variables for the parent shell. I thought about printing those messages inside the while-loop when I know that it's the last "aPathOfRepoDir" but that's kinda a "cheap" way to do it and won't be efficient. Is there another way?

Thanks in advance

score 2 · Accepted Answer · answered Nov 27 '18 at 16:44

Right hand side of a pipe runs in a subshell. Changes in the subshell variables don't propagate to the parent shell. Use process substitution instead:

while read -r aPathOfRepoDir
    do
        BASENAME=`basename "$aPathOfRepoDir"`
        if [[ -d "$aPathOfRepoDir" ]]; then
            totalDirectories=$((totalDirectories+1))
        elif [[ -f "$aPathOfRepoDir" ]] && [[ "$BASENAME" == *".txt" ]]; then
            totalTextFiles=$((totalTextFiles+1))
        else
            totalOtherFiles=$((totalOtherFiles+1))
        fi
    done < <(find assignments/"$repoDir" | grep -v .git | grep "$repoDir"/ )

score 0 · Answer 2 · answered Nov 27 '18 at 17:17

How about this:

classify() {
    local -A types=([dir]=0 [txt]=0 [other]=0)
    local n=0
    while read -r type path; do 
        if [[ $type == d ]]; then
            (( types[dir] ++ ))
        elif [[ $type == f && $path == *.txt ]]; then
            (( types[txt] ++ ))
        else
            (( types[other] ++ ))
        fi
        ((n++))
    done
    if [[ $n -gt 0 ]]; then
        echo "$1"
        echo "total directories: ${types[dir]}"
        echo "total text files: ${types[txt]}"
        echo "total other files: ${types[other]}"
    fi
}

for repoDir in assignments/*; do 
    find "$repoDir" \
        \( ! -path "$repoDir" -a ! -path '*/.git' -a ! -path '*/.git/*' \) \
        -printf '%y %p\n' \
    | classify "$repoDir"
done

find can exclude the files you don't want to see
find will also emit the file type to simplify the classification
the "classify" function will loop over the find output to count the various categories.
not parsing ls
the function helps to localize all the variables in a single subshell

This is vulnerable to filenames containing newlines, but that can be rectified. — glenn jackman, Nov 27 '18 at 17:23

Losing value of variables when exiting while-loop in bash

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