$1 and $2 variable shell script recursive is function is received as same-CodePudding

I have written a recursive function to iterate through directories, iteration should exit when the specified depth is reached. Both the entry directory and maximum depth value are passed as parameters to the function.

perform_fragmented_copy() { 
    echo -e "perform_fragmented_copy: $1 at depth $2"
    while [ "$1" ] && [ "$2" -le $n_max_depth ]; 
    do
        declare -i n_entry_size=$(du -sb $1  | awk '{print $1}')
        if [ $sz_remainig_destination -gt $n_entry_size ]
        then
            echo -e "perform_fragmented_copy: can do the copy";
        else
            echo -e "perform_fragmented_copy: cannot, iterating again";
            declare -i n_curr_depth=$(($2 1))
            perform_fragmented_copy "$1"/* $n_curr_depth
        fi
        shift
    done 
    echo -e "perform_fragmented_copy: exiting: $1 at depth $2"
}

Invoked as

sz_remainig_destination=10000
n_max_depth=5 
perform_fragmented_copy $1 0

Output is:

perform_fragmented_copy: /home/ROSS-82/ at depth 0
perform_fragmented_copy: cannot, iterating again
perform_fragmented_copy: /home/ROSS-82//82 at depth /home/ROSS-82//ross_reader-82
./ftest.sh: line 69: [: /home/ROSS-82//ross_reader-82: integer expression expected
perform_fragmented_copy: exiting: /home/ROSS-82//82 at depth /home/ROSS-82//ross_reader-82
./ftest.sh: line 69: [: : integer expression expected
perform_fragmented_copy: exiting: 0 at depth

In output at fist recursion $2 is received as integer which is 0

perform_fragmented_copy: /home/ROSS-82/ at depth 0

In output at second recursion $2 is received as $1

perform_fragmented_copy: /home/ROSS-82//82 at depth /home/ROSS-82//ross_reader-82

I have tried many ways to resolve this, and googled for solutions, but no results yet.

CodePudding user response：

You should move the depth to the first argument. Then you can shift this out of the argument list before the loop, and the loop processes the remaining arguments with $1 and shift.

perform_fragmented_copy() { 
    depth=$1
    shift
    echo -e "perform_fragmented_copy: $@ at depth $depth"

    if [ "$depth" -ge "$n_max_depth" ]
    then return
    fi
    declare -i n_curr_depth=$(($depth 1))

    while [ $# -gt 0 ]; 
    do
        declare -i n_entry_size=$(du -sb "$1" | awk '{print $1}')
        if [ $sz_remainig_destination -gt $n_entry_size ]
        then
            echo -e "perform_fragmented_copy: can do the copy";
        else
            echo -e "perform_fragmented_copy: cannot, iterating again";
            perform_fragmented_copy $n_curr_depth "$1"/* 
        fi
        shift
    done 
    echo -e "perform_fragmented_copy: exiting: at depth $depth"
}

You can't refer to $1 in the exiting message at the end, because the loop ends when all the parameters have been shifted away. The loop ends when $1 is empty.