Cleaner Way to load multiple environment variables into shell-CodePudding

I'm currently loading multiple variables into my shell (from a .env file) like so:

eval $(grep '^VAR_1' .env) && eval $(grep '^VAR_2' .env) && ...

I then use them in a script like so: echo $VAR_1.

Is there any way to condense this script into something like: eval $(grep ^('VAR_1|VAR_2')) .env? Maybe needs something other than grep

CodePudding user response：

You may use this grep with ERE option to filter all the variable you want from .env file:

grep -E '^(VAR_1|VAR_2)=' .env

This pattern will find VAR_1= or VAR_2= strings at the start.

To set variable use:

declare $(grep -E '^(VAR_1|VAR_2)=' .env)

# or
eval $(grep -E '^(VAR_1|VAR_2)=' .env)

CodePudding user response：

I would use source (.) command with process substitution:

. <(grep -e '^VAR_1=' -e '^VAR_2=' .env)

. <(grep '^VAR_[12]=' .env) # for this particular variables

The file .env must be from a trusted source, of course.