Function¶

Unlike functions in “real” programming languages, Bash functions don’t allow you to return a value when called. When a bash function completes, its return value is the status of the last statement executed in the function, 0 for success and non-zero decimal number in the 1 - 255 range for failure.

create a function¶

put the defined function in .bashrc and run source ~/.bashrc.

myfun() {
    mv "$1" "$1.bak"
    cp "$2" "$1"
}

how to return a value¶

using echo to return a value from a function

myfun() {
    echo $(( $1+1 ))
}