Variable assignment echo $VAR in subshell is a good method or not? (Nested bash functions)

I'm not a BASH programmer and whenever I have to create scripts it's a lottery for me, so apologies if my script looks too redudant or written by a newbie. As a foreword I have many screen snapshots taken on a Windows machine where the two display are captured. I organized them in subfolders and I want to take a general approach to crop images in them. As an aside, since I don't like filename as Windows generates them, i.e. with spaces and parenthesys, I want to remove such characters. All above is just one of many cases where I may have to apply actions to files residing in subfolders. I organized the script by actions to be taken on files. Now to the point: in wring the script I wanted it to be general purpose and hene I tried to have functions behaving like other scripting languages trying not to use global variables if not stricly necessary. Now the point: since I have to assign strings to variables eventually I was forced to use "echo -n" in a subshell I read opposite comments on usign echo in a subshell to assign a string made of spaces or other special characters to a variable. I tested one by one and on their own the three functions here below and they worked. That means that when required I forced values in the function itself. As soon as I nested them in the third one the only thing I know is that if I didn't use this tecnique of echoing the variable in a subshell and capturing the output it would never have worked: except for a variable, explained at the bottom. trim_weird_char () { # set +x local _bn="$(basename "$1")" # echo "[twc bn] $_bn" local _dn="$(dirname "$1")" # echo "[twc dn] $_dn" local _fn="$(echo -n $_bn | tr -d ' ' | tr -d '(' | tr -d ') ')" # echo "[twc fn] $_fn" local _ifn="$(echo -n "${_dn}"/"${_bn}")" local _dfn="$(echo -n "${_dn}"/"${_fn}")" mv "$_ifn" "$_dfn" echo "$_dfn" # set -x } crop_img() { # set +x #$1 = image #$2 = resize #$3 = string to add in the output filename before the extension local _img="$(echo -n "$1")"; # we want the file name and hence we remove the extension by NOT being GREEDY with the removal local _fn="$(echo -n "${_img%.*}")" local _ext="$(echo -n "${_img##*.}")"; # we want the extension and hence we remove what comes before by being GREEDY with the removal local _dfn="$(echo -n "${_fn}${3}.${_ext}")" convert "$_img" -crop "$2" "$_dfn" echo "$(echo -n "$_dfn")" } crop_smartbe () { # set -x # ls -la | awk '{print $5}' echo -n "Trimming name for $1..." local _img="$(trim_weird_char "$1")" echo "done: $_img" echo -n "Cropping $_img to... " local _s="$(ls -la "$_img" | awk '{print $5}')" local _dfn="$(echo -n $(crop_img "$_img" "1080x1920+0+0" "_cropped"))" local _s_img=$(ls -la "$_dfn" | awk '{print $5}') echo "$_dnf done: size from $_s to $_s_img" } A filename I tested my functions on is the following (I source'd the script above) gadger@brunas:/brunas/expenses/2020/Demandes de reimbursement/Demandes$ crop_smartbe Full/1261597\ -\ Frais\ Internet\ -\ 1er\ sémestre/Screenshot\ \(142\).png Trimming name for Full/1261597 - Frais Internet - 1er sémestre/Screenshot (142).png...done: Full/1261597 - Frais Internet - 1er sémestre/Screenshot142.png Cropping Full/1261597 - Frais Internet - 1er sémestre/Screenshot142.png to... done: size from 292631 to 100694 For this (in crop_smartbe) local _dfn="$(echo -n $(crop_img "$_img" "1080x1920+0+0" "_cropped"))" ... echo "$_dnf done: size from $_s to $_s_img" still $_dnf is not assigned correctly even though I used the echo -n tecnique. Taken for granted that removing the echo function breaks the script, shall I prefer printf instead? Or should I rewrite the script in a different manner that doesn't require the use of echo? In case how? Thanks Alex