How to use a goto statement in a shell script
As others have pointed out, in bash
(or other POSIX-like shells) there is no goto
) - other, more flexible flow control constructs are taken in its place.
Find the title Compound Commands
in man bash
.
In your case, the command select
is the right choice. Since the use of this may not be obvious, here's what you need to get 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 $choice in
copy)
echo "Copying..."
# Set flag here, or call function, ...
;;
exit)
echo "Exiting. "
exit 0
esac
# Getting here means that a valid choice was made,
# so break out of the select statement and continue below,
# if desired.
# Note that without an explicit break (or exit) statement,
# bash will continue to prompt.
break
done
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Here's a quick example using a loop select
to accomplish your goal. You can use a while
custom menu loop if you want to customize the formatting, but the main menu is what was designed select
:
#!/bin/bash
## array of menu entries
entries=( "for Copy"
"for exit" )
## set prompt for select menu
PS3='Selection: '
while [ "$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 / Exit
$ 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
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