local

Declare local variables in functions.

Source: src/execution/builtins.f90:2307-2371

Synopsis

local [option] name[=value] ...

Description

The local builtin creates variables that are scoped to the current function. Local variables shadow global variables of the same name.

Options

Same as declare:

Usage

Basic Local Variable

myfunc() {
    local myvar="local value"
    echo "$myvar"
}

myvar="global value"
myfunc          # "local value"
echo "$myvar"   # "global value"

Multiple Variables

func() {
    local a=1 b=2 c=3
    echo "$a $b $c"
}

Local Arrays

func() {
    local -a arr=(one two three)
    local -A map=([key]=value)

    echo "${arr[0]}"
    echo "${map[key]}"
}

Local Integer

counter() {
    local -i count=0
    count=count+1   # No $(()) needed
    echo $count
}

Examples

Prevent Global Pollution

process_files() {
    local file
    local count=0

    for file in *.txt; do
        ((count++))
    done

    echo "Processed $count files"
}
# $file and $count don't exist after function

Recursive Function

factorial() {
    local -i n=$1

    if [[ $n -le 1 ]]; then
        echo 1
    else
        local -i prev=$(factorial $((n-1)))
        echo $((n * prev))
    fi
}

factorial 5   # 120

Shadow Global

name="global"

greet() {
    local name="local"
    echo "Hello, $name"
}

greet              # "Hello, local"
echo "$name"       # "global"

Modify Global Intentionally

counter=0

increment() {
    # No 'local' - modifies global
    ((counter++))
}

increment
echo $counter   # 1

Scope Rules

Dynamic Scope

Child functions see parent's local variables:

outer() {
    local x="from outer"
    inner
}

inner() {
    echo "$x"   # Sees outer's x
}

outer   # "from outer"

Shadowing Chain

x="global"

level1() {
    local x="level1"
    level2
}

level2() {
    local x="level2"
    echo "$x"   # "level2"
}

level1
echo "$x"   # "global"

Implementation

Source: builtins.f90:2307-2371

• Only valid inside functions (checks function_depth > 0)
• Variables stored in shell%local_vars 2D array
• Indexed by [function_depth, variable_index]
• Limit: MAX_LOCAL_VARS per function level

Exit Status

Notes

• local outside function is an error
• local creates new variable (doesn't modify global)
• Readonly locals can't be modified
• Exported locals are exported

Comparison

See Also

• declare - Declare with attributes
• Functions - Function documentation
• Variables - Variable overview