Looping over shell script arguments and passing quoted arguments to function

Question

I have a script below that sources a directory of bash scripts and then parses the flags of the command to run a specific function from the sourced files.

Given this function within the scripts dir:

function reggiEcho () {
  echo $1
}

Here are some examples of current output

$ reggi --echo hello
hello
$ reggi --echo hello world
hello
$ reggi --echo "hello world"
hello
$ reggi --echo "hello" --echo "world"
hello
world

As you can see quoted parameters are not honored as they should be `"hello world" should echo properly.

This is the script, the issue is within the while loop.

How do I parse these flags, and maintain passing in quoted parameters into the function?

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
STR="$(find $DIR/scripts -type f -name '*.sh' -print)"
ARR=( $STR )
TUSAGE="\n"

for f in "${ARR[@]}"; do
    if [ -f $f ]
    then
        . $f --source-only

        if [ -z "$USAGE" ]
        then
            :
        else
            TUSAGE="$TUSAGE \t$USAGE\n"
        fi

        USAGE=""
    else
        echo "$f not found"
    fi
done 

TUSAGE="$TUSAGE \t--help (shows this help output)\n"

function usage() {
  echo "Usage: --function <args> [--function <args>]"
  echo $TUSAGE
  exit 1
}

HELP=false

cmd=()
while [ $# -gt 0 ]; do                         # loop until no args left

    if [[ $1 = '--help' ]] || [[ $1 = '-h' ]] || [[ $1 = '--h' ]] || [[ $1 = '-help' ]]; then
        HELP=true
    fi

    if [[ $1 = --* ]] || [[ $1 = -* ]]; then                    # arg starts with --
        if [[ ${#cmd[@]} -gt 0 ]]; then
            "${cmd[@]}"
        fi
        top=`echo $1 | tr -d -`                              # remove all flags
        top=`echo ${top:0:1} | tr  '[a-z]' '[A-Z]'`${top:1}  # make sure first letter is uppercase
        top=reggi$top                                         # prepend reggi
        cmd=( "$top" )                                       # start new array
    else
        echo $1
        cmd+=( "$1" )
    fi
    shift
done

if [[ "$HELP" = true ]]; then
    usage
elif [[ ${#cmd[@]} -gt 0 ]]; then
    ${cmd[@]}
else
    usage
fi

Answer 1

There are many places in this script where you have variable references without double-quotes around them. This means the variables' values will be subject to word spitting and wildcard expansion, which can have various weird effects.

The specific problem you're seeing is due to an unquoted variable reference on the fourth-from-last line, ${cmd[@]} . With cmd=( echo "hello world" ) , word splitting makes this equivalent to echo hello world rather than echo "hello world" .

Fixing that one line will fix your current problem, but there are a number of other unquoted variable references that may cause other problems later. I recommend fixing all of them. Cyrus' recommendation of shellcheck.net is good at pointing them out, and will also note some other issues I won't cover here. One thing it won't mention is that you should avoid all-caps variable names ( DIR , TUSAGE , etc) -- there are a bunch of all-caps variables with special meanings, and it's easy to accidentally reuse one of them and wind up with weird effects. Lowercase and mixed-case variables are safer.

I also recommend against using \\t and \\n in strings, and counting on echo to translate them into tabs and newlines, respectively. Some versions of echo do this automatically, some require the -e option to tell them to do it, some will print "-e" as part of their output... it's a mess. In bash, you can use $'...' to translate those escape sequences directly, eg:

tusage="$tusage"$' \t--help (shows this help output)\n'    # Note mixed quoting modes
echo "$tusage"    # Note that double-quoting is *required* for this to work right

You should also fix the file listing so it doesn't depend on being unquoted (see chepner's comment). If you don't need to scan subdirectories of $DIR/scripts, you can do this with a simple wildcard (note lowercase vars and that the var is double-quoted, but the wildcard isn't):

arr=( "$dir/scripts"/*.sh )

If you need to look in subdirectories, it's more complicated. If you have bash v4 you can use a globstar wildcard, like this:

shopt -s globstar
arr=( "$dir/scripts"/**/*.sh )

If your script might have to run under bash v3, see BashFAQ #20: "How can I find and safely handle file names containing newlines, spaces or both?" , or just use this:

while IFS= read -r -d '' f <&3; do
    if [ -f $f ]
        # ... etc
done 3< <(find "$dir/scripts" -type f -name '*.sh' -print0)

(That's my favorite it-just-works idiom for iterating over find 's matches. Although it does require bash, not some generic POSIX shell.)