space_to_underscore.sh

#!/bin/bash
#=============================================================#
# Name:         Space to Underscore                           #
# Description:  Recursively replace spaces with underscores   #
#               in file and directory names.                  #
# Version:      ver 1.2                                       #
# Data:         16.6.2014                                     #
# Author:       Arthur Gareginyan                             #
# Author URI:   https://www.arthurgareginyan.com              #
# Email:        arthurgareginyan@gmail.com                    #
# License:      GNU General Public License, version 3 (GPLv3) #
# License URI:  http://www.gnu.org/licenses/gpl-3.0.html      #
#=============================================================#

#               	USAGE:
#		chmod +x space_to_underscore.sh
#		cd /home/user/example
#		~/space_to_underscore.sh "find_this" "replace_with_this"

# Check for proper priveliges
[ "`whoami`" = root ] || exec sudo "$0" "$@"


####################### DIALOG ############################
echo -en "\n BEWARE! Starting from current directory (`pwd`),"
echo -en " files and directories with spaces in name  will be renamed automatically.\n"
echo -en "\n Press \"ENTER\" to continue or \"N\" to exit:"
read ops
case "$ops" in
        n|N)
            echo -en "\n Canceled by User. Exiting...\n"
            exit 1 ;;
        *)
            echo -en "\n Begining...\n" ;;
esac


################### SETUP VARIABLES #######################
number=0                    # Number of renamed.
number_not=0		    # Number of not renamed.
IFS=$'\n'
array=( `find ./ -type d` ) # Find catalogs recursively.


######################## GO ###############################
# Reverse cycle.
for (( i = ${#array[@]}; i; )); do
     # Go in to catalog.
     pushd "${array[--i]}" >/dev/null 2>&1
     # Search of all files in the current directory.
     for name in *
     do
     	     # Check for spaces in names of files and directories.
	     echo "$name" | grep -q "$1"
	     if [ $? -eq 0 ]
	     then
	     	# Replacing spaces with underscores.
	        newname=`echo $name | sed -e "s/$1/$2/g"`
		if [ -e $newname ]
        	then
			let "number_not +=1"
                	echo " Not renaming: $name"
        	else
        		# Plus one to number.
                	let "number += 1"
                    	# Message about rename.
                	echo "$number Renaming: ${array[i]}/$name"
                	# Rename.
		        mv "$name" "$newname"
		fi
	     fi
     done
     # Go back.
     popd >/dev/null 2>&1
done

echo -en "\n All operations is complited."

if [ "$number_not" -ne "0" ]
  then echo -en "\n $number_not not renamed."
fi

if [ "$number" -eq "0" ]
  then echo -en "\n Nothing been renamed.\n"
elif [ "$number" -eq "1" ]
   then echo -en "\n $number renamed.\n"
   else echo -en "\n Renamed files and catalogs: $number\n"
fi

exit 0