Shell – How to remove space in all sub directories in shell script

Use this with bash:

find $1 -name "* *.xml" -type f -print0 | \
  while read -d $'\0' f; do mv -v "$f" "${f// /_}"; done

find will search for files with a space in the name. The filenames will be printed with a nullbyte (-print0) as delimiter to also cope with special filenames. Then the read builtin reads the filenames delimited by the nullbyte and finally mv replaces the spaces with an underscore.

EDIT: If you want to remove the spaces in the directories too, it's a bit more complicated. The directories are renamed and then not anymore accessible by the name find finds. Try this:

find -name "* *" -print0 | sort -rz | \
  while read -d $'\0' f; do mv -v "$f" "$(dirname "$f")/$(basename "${f// /_}")"; done

The sort -rz reverses the file order, so that the deepest files in a folder are the first to move and the folder itself will be the last one. So, there are never folders renamed before all files and folder are rename inside of it. The mv command in the loop is a bit changed too. In the target name, we only remove the spaces in the basename of the file, else it wouldn't be accessible.

After you cd to the correct directory, this script will reliably solve your need (not portable because of the ${var//pat/str} expansion):

#!/bin/bash

set -- *_*
for file; do
    mv -- "$file" "${file//_/ }"
done

*_* The glob *_* will select all files that have an _ in their names.

set -- Those names (even including spaces or new-lines) will be reliably set to the positional parameters $1, $2, etc. with the simple command set -- "list"

for file; Then, each positional parameter will be (in turn) assigned to the var file.

do ... done contains the commands to execute (for each $file).

mv -- "$file" "${file//_/ }" will move (rename) each file to the same name with each (all) _ replaced by (space).

Note: You may add the -i (interactive) option to avoid overwriting already existing files. If the file exist, mv will ask. With a caveat: there needs to be an interactive shell where mv could communicate with the user.

mv -i -- "$file" "${file//_/ }"