Modify

#!/bin/sh
# Write a script modify with the following syntax:

#   modify [-r] [-l|-u] <dir/file names...>
#   modify [-r] <sed pattern> <dir/file names...>
#   modify [-h]

#   modify_examples

# which will modify file names. The script is dedicated to lowerizing (-l)
# file names, uppercasing (-u) file names or internally calling sed
# command with the given sed pattern which will operate on file names.
# Changes may be done either with recursion (-r) or without it. Write a
# second script, named modify_examples, which will lead the tester of the
# modify script through the typical, uncommon and even incorrect scenarios
# of usage of the modify script.

#VARIABLES
RECURSIVE_MODE=0
LOWERCASE=0
UPPERCASE=0
SED_MODE=0
MODE=0  #lowercasing:1 uppercasing:2 sed_pattern:3
SED_PATTERN=""
SCRIPTNAME=`basename $0`
#echo "My name is $SCRIPTNAME\n"

printHelp(){
    echo "Usage:\n\t$0 [-r] [-l|-u] <dir/file names...>\n\t$0 [-r] <sed pattern> <dir/file names...>\n\t$0 [-h]\n "
    echo "Where:\n\t-l lowerizes specified filenames\n\t-u uppersizes specified filenames"
    echo "\t-r runs the script with recursion\n\t-h prints this help\n"
}

modifySingleFile(){
        CURRENT_NAME=`basename "$1"`
        CURRENT_PATH=`dirname "$1"`

        #Don't modify yourself
        if [ "$CURRENT_NAME" = "$SCRIPTNAME" ] ; then
            return
        fi

        case $MODE in
            "1") NEW_NAME=`echo "$CURRENT_NAME" |  tr [:upper:] [:lower:]` ;;
            "2") NEW_NAME=`echo "$CURRENT_NAME" |  tr [:lower:] [:upper:]` ;;
            "3") NEW_NAME=`echo "$CURRENT_NAME" |  sed -s $SED_PATTERN` ;;
        esac

        #New filename is prepared, check if modifying the name won't override anything
        if [ -f "$CURRENT_PATH/$NEW_NAME" ] ; then
             `echo "File $NEW_NAME already exists, name modifying failed" 1>&2`
            return
        else
            mv "$1" "$CURRENT_PATH/$NEW_NAME"
            CNT=$((CNT+1))
        fi
}
modifyNames(){
    #At first, check if the file exists
    if [ ! -f "$1" -a ! -d "$1" ] ; then
            `echo "Neither file nor directory --$1-- exists" 1>&2`
            return
    fi

    if [ ! -w "$1" -a -f "$1" ]; then
        `echo "File $1 cannot be modified" 1>&2`
        return
    fi

    if [ $RECURSIVE_MODE -eq 1 ] ; then
        if [ -d "$1" ] ; then
         # find "$1" -depth -type d | while read -r dir ; do #echo "$dir"
            find "$1"  -depth -type f | while read -r file ; do #echo "$file"
                # echo "\t\t\t\t\t3"
                modifySingleFile "$file"
            done
         # done
        else    #$1 is not a directory
            # echo "\t\t\t\t1"
        modifySingleFile "$1"
        fi
    else        #Recursive mode is off
        # echo "\t\t\t\t2"
        modifySingleFile "$1"
    fi
}

if [ $# -eq 0 ]; then
    printHelp
fi

while [ "$1" != "" ]; do
    case "x$1" in
        "x-r")  RECURSIVE_MODE=1 ;;
        "x-l")  MODE=1 ;;
        "x-u")  MODE=2 ;;
        "x-h")  printHelp
                exit ;;
        *)
        #current argument is not a parameter, it can be a sed pattern,a directory or a filename
        if [ $MODE -eq 0 ]; then
            MODE=3
            SED_PATTERN="$1"
        else
            modifyNames "$1"
        fi
        ;;
    esac
shift
done