CODEWITHSUNDEEP
bashshellzsh
4015.alt
4015.alt

Reputation: 75

How to prevent sourcing a part of a bash script?

I have a shell script with a syntax compatible to both bash and zsh, except for a section that has zsh specific syntax. that throws syntax errors if sourced from a bash is there an easy way to escape such section when using bash.

The script is a bash function that sources all the files in a directory. it works fine form zsh (and it is irrelevant to the question)

#!/usr/bin/env bash

shell=$(ps -p $$ -oargs=)

if [ $shell = "bash" ]; then
    for f in ~/.functions.d/*.sh; do source $f; done
elif [ $shell = "zsh" ]; then
    for f (~/.functions.d/**/*.sh) source $f
fi

the error is produced by the 7th line, when sourcing it in bash

relevant links

Upvotes: 0

Views: 568

Answers (2)

user1934428
user1934428

Reputation: 22366

I would do a

if [[ -n ${BASH_VERSION:-} ]]
then
   : we are in bash
else
   : we are not
fi

The variable BASH_VERSION is guaranteed to be set by bash, and unless you are explicitly (malevolently) tamper with this variable, you should be fine.

Upvotes: 0

Barmar
Barmar

Reputation: 782653

The problem is that the entire if/elif/else statement is parsed as a unit, so it can't contain invalid syntax.

What you could do is exit the sourced script before executing the zsh-specific code:

shell=$(ps -p $$ -oargs=)

if [ $shell = "bash" ]; then
    for f in ~/.functions.d/*.sh; do source $f; done
    return
fi

if [ $shell = "zsh" ]; then
    for f (~/.functions.d/**/*.sh) source $f
fi

However, a more general solution is to extract the bash-specific and zsh-specific code into separate scripts.

shell=$(ps -p $$ -oargs=)

if [ $shell = "bash" ]; then
    source load_functions.bash
fi

if [ $shell = "zsh" ]; then
    source load_functions.zsh
fi

load_functions.bash would contain the first for loop, while load_functions.zsh would have the second one.

           

Upvotes: 4

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