rename.sh

#!/bin/bash

function _help-flag() {
    [[ " ${@} " == *" --help "* ]] || [[ " ${@} " == *" -h "* ]]
}

if _help-flag "${@}" || [ $# -lt 3 ] ; then
    echo "Usage: ${0} <STR1> <STR2> FILE..."
    echo
    echo "Rename a bunch of files by replacing STR1 with STR2 in their filename."
    exit 2
fi

str1=$1
str2=$2
shift 2

for f in "$@"; do
    echo "${f} => ${f/$str1/$str2}"
done | column -t

echo Proceed with renaming? [yes / no]
read -r answer

if [ "${answer}" = "yes" ]; then
    for f in "$@"; do
        mv "${f}" "${f/$str1/$str2}"
    done
fi