How to use goto statement in shell script

Question

I am beginner in shell script. I don't have any idea about how to use goto statement. I am using the following code.

start:
echo "Main Menu"
echo "1 for Copy"
echo "2 for exit"
read NUM
case $NUM in
"1")
echo "CopyNUM"
goto start:;
"2")         
echo "Haiiii";
goto start:
*)
echo "ssss";
esac

http://stackoverflow.com/questions/9639103/is-there-a-goto-statement-in-bash — woahguy, May 12 '15 at 05:02
If you check `man bash` you will not find `goto` -- there is a reason. There is no `goto` in bash. If you want branching control, you have `loops`, `select`, `case`, `functions` and `if then else`. Those will meet your need is a much more elegant manner. In your case above, a `select` or a `while` loop is what you want. — David C. Rankin, May 12 '15 at 05:10

score 3 · Accepted Answer · answered May 12 '15 at 05:33

As others have noted, there's no goto in bash (or other POSIX-like shells) - other, more flexible flow-control constructs take its place.
Look for heading Compound Commands in man bash.

In your case, the select command is the right choice. Since how to use it may not be obvious, here's something to get you started:

#!/usr/bin/env bash

echo "Main Menu"

# Define the choices to present to the user, which will be
# presented line by line, prefixed by a sequential number
# (E.g., '1) copy', ...)
choices=( 'copy' 'exit' )

# Present the choices.
# The user chooses by entering the *number* before the desired choice.
select choice in "${choices[@]}"; do

  # If an invalid number was chosen, $choice will be empty.
  # Report an error and prompt again.
  [[ -n $choice ]] || { echo "Invalid choice." >&2; continue; }

  # Examine the choice.
  # Note that it is the choice string itself, not its number
  # that is reported in $choice.
  case $choice in
    copy)
      echo "Copying..."
      # Set flag here, or call function, ...
      ;;
    exit)
      echo "Exiting. "
      exit 0
  esac

  # Getting here means that a valid choice was made,
  # so break out of the select statement and continue below,
  # if desired.
  # Note that without an explicit break (or exit) statement, 
  # bash will continue to prompt.
  break

done

score 2 · Answer 2 · answered May 12 '15 at 05:41

Here is a short example using a select loop to accomplish your goal. You can use a while loop with a custom menu if you want custom formatting, but the basic menu is what select was designed to do:

#!/bin/bash

## array of menu entries
entries=( "for Copy"
          "for exit" )

## set prompt for select menu
PS3='Selection: '

while [ "$menu" != 1 ]; do                ## outer loop redraws menu each time
    printf "\nMain Menu:\n\n"             ## heading for menu
    select choice in "${entries[@]}"; do  ## select displays choices in array
        case "$choice" in                 ## case responds to choice
            "for Copy" )
                echo "CopyNUM"
                break                     ## break returns control to outer loop
                ;;
            "for exit" )         
                echo "Haiiii, exiting"
                menu=1                    ## variable setting exit condition
                break
                ;;
            * )
                echo "ssss"
                break
                ;;
        esac
    done
done

exit 0

Use/Output

$ bash select_menu.sh

Main Menu:

1) for Copy
2) for exit
Selection: 1
CopyNUM

Main Menu:

1) for Copy
2) for exit
Selection: 3
ssss

Main Menu:

1) for Copy
2) for exit
Selection: 2
Haiiii, exiting

How to use goto statement in shell script

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