Shell Scripts and Functions

[TSch]

Hi folks,

I'm currently trying to figure out the possibilities of using functions within shell scripts.

Now I'm facing my first Problem

I'm trying to create a menu structure from where I can jump between different menues and always go back to my main menu ...

e.G.

#!/usr/bin/ksh

function main
{
echo "Please choose:"
echo "1) Do something"
echo "2) Do something else"
echo "3) Do something completely different"
echo ""
read $1

case $1 in
  1) function_1
  2) function_2
  3) function_3
esac
}

function function_1
{
echo "Something ..."
... perform certain actions
echo "Press any key to return to main menu"
read $1
main
}

function function_2
{
echo "Something else ..."
... perform certain actions
echo "Press any key to return to main menu"
read $1
main
}

function function_3
{
echo "Something completely different..."
... perform certain actions
echo "Press any key to return to main menu"
read $1
main
}

main

-> Now the problem is, that I keep calling new functions without quitting the old function I'd like to leave and therefore continue to consume more memory on my machine each time I call another function. e.G.: jumping from main to function_1 and from there to main. After that I got 2xmain function active as well as 1xfunction_1 active. Then I jump to function_3 and back to main and voila: 3xmain active, 1xfunction_1 active AND 1xfunction_3 active ...

What would be the best way to end an old function as soon as I jump to another function ?

Regards
Thomas

 

[feherke]

Hi

Use a loop and call main only in that :

[gray]#!/usr/bin/ksh[/gray]

[COLOR=darkgoldenrod]function main[/color]
{
  echo [green][i]"Please choose:"[/i][/green]
  echo [green][i]"1) Do something"[/i][/green]
  echo [green][i]"2) Do something else"[/i][/green]
  echo [green][i]"3) Do something completely different"[/i][/green]
  echo [green][i]"anything else) Do nothing ( Yeah, I mean Exit )"[/i][/green]
  [COLOR=chocolate]read[/color] choice

  [b]case[/b] [green][i]"$choice"[/i][/green] [b]in[/b]
    [purple]1[/purple][teal])[/teal] function_1 [teal];;[/teal]
    [purple]2[/purple][teal])[/teal] function_2 [teal];;[/teal]
    [purple]3[/purple][teal])[/teal] function_3 [teal];;[/teal]
    [teal]*)[/teal] [navy]choice[/navy][teal]=[/teal][purple]0[/purple] [teal];;[/teal]
  [b]esac[/b]

  [teal](([/teal] choice [teal]))[/teal] [teal]&&[/teal] {
    echo [green][i]"Press any key to return to main menu"[/i][/green]
    [COLOR=chocolate]read[/color]
  }

  [COLOR=chocolate]return[/color] [green][i]"$choice"[/i][/green]
}

[COLOR=darkgoldenrod]function function_1[/color]
{
  echo [green][i]"Something ..."[/i][/green]
  [gray]# ... perform certain actions[/gray]
}

[COLOR=darkgoldenrod]function function_2[/color]
{
  echo [green][i]"Something else ..."[/i][/green]
  [gray]# ... perform certain actions[/gray]
}

[COLOR=darkgoldenrod]function function_3[/color]
{
  echo [green][i]"Something completely different..."[/i][/green]
  [gray]# ... perform certain actions[/gray]
}

[b]until[/b] main[teal];[/teal] [b]do[/b] [teal]:;[/teal] [b]done[/b]

Tested with [tt]mksh[/tt].

Feherke.

http://free.rootshell.be/~feherke/