Qfyilyi

I want to add the third parameter that will be changing files name from upper to lower OR lower to upper but in this third parameter I want to specify what file's name must be changed? What's wrong with this script? Thank you in advance.

#!/bin/bash



if test "$1" = "lower" && test "$2" = "upper"

then

    for file in *; do

        if [ $0 != "$file" ] && [ $0 != "./$file" ]; then

        mv "$file" "$(echo $file | tr [:lower:] [:upper:])";

        fi

fi

done



elif test "$1" = "upper" && test "$2" = "lower"

then

    for file in *; do

    if [ $0 != "$file" ] && [ $0 != "./$file" ]; then

    mv "$file" "$(echo $file | tr [:upper:] [:lower:])";

    fi

done

fi



if [ "$1" = "lower" ] && [ "$2" = "upper" ] && [ "$3" = "$file" ]; 

then

    for file in * ; do

    if [ $0 != "$file" ] && [ $0 != "./$file" ]; then

    mv "$file" "$(echo $file | tr [:lower:] [:upper:])";

    fi

done

fi

If I am guessing correctly what you want, try

#!/bin/bash



case $1:$2 in

 upper:lower | lower:upper ) ;;

 *) echo "Syntax: $0 upper|lower lower|upper files ..." >&2; exit 1;;

esac



from=$1

to=$2

shift; shift

for file; do

    mv "$file" "$(echo "$file" | tr "[:$from:]" "[:$to:]")"

done

This has the distinct advantage that it allows more than three arguments, where the first two specify the operation to perform.

Notice also how we take care to always quote strings which contain a file name. See also When to wrap quotes around a shell variable?

The above script should in fact also work with /bin/sh; we do not use any Bash-only features so it should run under any POSIX sh.

However, a much better design would probably be to use an option to decide what mapping to apply, and simply accept a (possibly empty) list of options and a list of file name arguments. Then you can use Bash built-in parameter expansion, too. Case conversion parameter expansion operations are available in Bash 4 only, though.

#!/bin/bash



op=',,'

# XXX FIXME: do proper option parsing

case $1 in -u) op='^^'; shift;; esac



for file; do

    eval mv "$file" "${file$op}"

done

This converts to lowercase by default, and switches to uppercase instead if you pass in -u before the file names.

In both of these scripts, we use for file as a shorthand for for file in "$@" i.e. we loop over the (remaining) command-line arguments. Perhaps this is the detail you were looking for.

Forgive me if I grossly misunderstand, but I think you may have misunderstood how argument passing works.

The named/numbered arguments represent the values you pass in on the command line in their ordinal positions. Each can theoretically have any value that can by stuck in a string. You don't need a third parameter, just a third value.

Let's try a sample.

#! /bin/env bash



me=${0#*/} # strip the path

use="

   $me { upper | lower } file



   changes the NAME of the file given to be all upper or all lower case.



"

# check for correct arguments

case $# in

2) : exactly 2 arguments passed - this is correct ;;

*) echo "Incorrect usage - $me requires exactly 2 arguments $use" >&2

   exit 1 ;;

esac



declare -l lower action # these variables will downcase anything put in them

declare -u upper        # this one will upcase anything in it

declare newname         # create a target variable with unspecified case



action="$1"             # stored the *lowercased* 1st argument passed as $action

case $action in         # passed argument has been lowercased for simpler checking

upper) upper="$2"       # store *uppercased* 2nd arg.

       newname="$upper" # newname is now uppercase.

       ;;

lower) lower="$2"       # store *lowercased* 2nd arg.

       newname="$lower" # newname is now lowercase.

       ;;

    *) echo "Incorrect usage - $me requires 2nd arg to be 'upper' or 'lower' $use" >&2

       exit 1 ;;

esac



if [[ -e "$2" ]]        # confirm the argument exists

then echo "Renaming $2 -> $newname:"

     ls -l "$2"

     echo " -> "

     mv "$2" "$newname" # rename the file

     ls -l "$newname"

else echo "'$2' does not exist. $use" >&2

     exit 1

fi

First of all there is indentation problem with this script check first if condition done should be coming before fi

Below is the correct.

if test "$1" = "lower" && test "$2" = "upper"

then



  for file in *; do

      if [ $0 != "$file" ] && [ $0 != "./$file" ]; then

      mv "$file" "$(echo $file | tr [:lower:] [:upper:])";

      fi

  done

fi

Secondly the question you asked:

#/bin/bash -xe 



[ $# -ne 3 ] && echo "Usage: {lower} {upper} {fileName} " && exit 1 

if [ "$1" = "lower" ] && [ "$2" = "upper" ] && [ -f "$3" ]; 

then 

  mv "$3" "$(echo $3 | tr [:lower:] [:upper:])"; 

fi 

Hope this helps.