bash

Validata correct number of arguments if [ "$#" -ne 2 ]; then echo "Illegal number of parameters ($#, should be 2)" exit 1 fi $# returns number of parameters passed to script. If it’s less then 2, script ends with error. Check if environment variable is set if [ -z "$CLEANING_JOB" ] then echo "Environmental variable [CLEANING_JOB] does not exist." exit 1 fi Bash function example set_dir_structure() { YEAR=$(date +"%Y" "$@") MONTH=$(date +"%m" "$@") DAY=$(date +"%d" "$@") HOUR=$(date +"%H" "$@") retval="$YEAR/$MONTH/$DAY/$HOUR" } This function can be executed with or without parameter to get proper dir structure related with date and time....

Simple example of bash script that is changing files extension in desired directory: #!/bin/bash CURRENT_EXTENSION="${1-mp3}" NEW_EXTENSION="${2-mp4}" FILES_PATH="${3-$PWD}" FILES_LIST=$(find ${FILES_PATH} -maxdepth 1 -name "*.${CURRENT_EXTENSION}") for FILE in $FILES_LIST; do NEW_FILE=$(echo "$FILE" | sed "s/${CURRENT_EXTENSION}/${NEW_EXTENSION}/") echo "Renaming file: $FILE -> $NEW_FILE" mv $FILE $NEW_FILE done Usage You can use it by simple executing file: ./change_ext.sh It will be executed with default settings: extensions to change: mp3, new extension will be mp4 and script will look for files in current directory....