I have a linux bash script with a function:
myfunctiona ()
{
local MYVAR1="one"
local MYVAR2="two"
echo $MYVAR1
# The line beneath is the line in question!
local MYVAR1=$MYVAR1$MYVAR2
}
When I want to give the LOCAL variable MYVAR1 in the function myfunctiona a new value, do I have to write
local MYVAR1=$MYVAR1$MYVAR2
or can I also write
MYVAR1=$MYVAR1$MYVAR2
With the second line without "local" do I create a global variable with the same name?
Once you've defined a local variable you can assign it normally, like this:
#!/bin/bash
myfunctiona ()
{
local MYVAR1="one"
local MYVAR2="two"
echo $MYVAR1
# The line beneath is the line in question!
local MYVAR1=$MYVAR1$MYVAR2
MYVAR1="FOO"
echo $MYVAR1
}
myfunctiona
echo "global" $MYVAR1
which gives the output:
one
FOO
global
HTH
The correct way to do it would be:
MYVAR1="${MYVAR1}${MYVAR2}"
The braces are usually used when you concatenate variables. Use quotes.
The variable is still local since you reassigned its value within the scope of the function. An example:
#!/usr/bin/env bash
_myFunction()
{
local var_1="one"
local var_2="two"
local -g var_3="three" # The -g switch makes a local variable a global variable
var_4="four" # This will be global since we didn't mark it as a local variable from the start
var_1="${var_1}${var_2}"
echo "Inside function var_1=${var_1}"
echo "Inside function var_2=${var_2}"
echo "Inside function var_3=${var_3}"
echo "Inside function var_4=${var_4}"
}
_myFunction
echo "Outside function var_1=${var_1}"
echo "Outside function var_2=${var_2}"
echo "Outside function var_3=${var_3}"
echo "Outside function var_4=${var_4}"
This results in:
$ ./script
Inside function var_1=onetwo
Inside function var_2=two
Inside function var_3=three
Inside function var_4=four
Outside function var_1=
Outside function var_2=
Outside function var_3=three
Outside function var_4=four
You can give this way, but as Ube said for concatenation you need to give like that -
MYVAR1="$MYVAR1$MYVAR2";
Even this works for concatenation
MYVAR1="$MYVAR1$MYVAR2";