How can I set environment variable for just one command in fish shell?

Question

In bash, I can do EDITOR=vim crontab -e. Can I get similar effect in Fish shell?

score 92 · Answer 1 · answered May 17 '13 at 13:44

92

Don't see why this shouldn't work: env EDITOR=vim crontab -e
That bypasses the shell completely.

answered May 17 '13 at 13:44

Wayne

1,021

4

This is so much easier. The only problem is that bypassing the shell disallows any custom fish commands, which are probably locked in your muscle memory. – TerraMetta Jun 03 '13 at 20:11
1

I saw that in the docs too, but then why doesn't the following work? env SOME_VAR=1 echo $SOME_VAR – lmsurprenant Nov 01 '17 at 22:50
1

never mind, i should have just looked it up: https://stackoverflow.com/questions/10938483/bash-specifying-environment-variables-for-echo-on-command-line – lmsurprenant Nov 01 '17 at 22:57

score 35 · Accepted Answer · answered Jul 27 '10 at 01:58

35

begin; set -lx EDITOR vim; crontab -e; end

answered Jul 27 '10 at 01:58

Dennis Williamson

62,879

5

is there any easier way to do this? – Milovan Zogovic Oct 29 '12 at 08:43
oddly, this doesn't work for me. I'm calling a ruby script, and ENV doesn't pick up the variable I'm setting: set -lx date '12/04/2012' – Duke Dec 07 '12 at 23:13
@Duke: It works for me. begin; set -lx date '12/04/2012'; ruby -e 'puts ENV["date"]'; end – Dennis Williamson Dec 08 '12 at 00:49
11

In the meanwhile this has been answered in the Fish FAQ: http://fishshell.com/docs/current/faq.html#faq-single-env – harm Apr 03 '14 at 09:09
4

And what that FAQ says is this: env SOME_VAR=1 command – BallpointBen Jun 05 '18 at 20:54

score 15 · Answer 3 · answered Mar 02 '15 at 15:59

That is from the Documentation

SOME_VAR=1 command produces an error: Unknown command "SOME_VAR=1".

Use the env command.

env SOME_VAR=1 command

You can also declare a local variable in a block and that would not bypass the shell

begin
  set -lx SOME_VAR 1
  command
end

score 6 · Answer 4 · answered Feb 20 '22 at 03:38

6

Starting version 3.1, you can use the same syntax used in bash (EDITOR=vim crontab -e).

PR introducing the feature: https://github.com/fish-shell/fish-shell/pull/6287

answered Feb 20 '22 at 03:38

Kevin Languasco

161

score 2 · Answer 5 · answered Feb 13 '17 at 02:18

depending on a definition of be function, this can fail

begin
  set -lx RAILS_ENV staging
  be rails r "p ENV['RAILS_ENV']"
end

In order for it to work:

function be --description 'Runs bundle exec' --no-scope-shadowing
  bundle exec $argv
end

Please, see the explanation of --no-scope-shadowing option

-S or --no-scope-shadowing allows the function to access the variables of calling functions. Normally, any variables inside the function that have the same name as variables from the calling function are "shadowed", and their contents is independent of the calling function.

How can I set environment variable for just one command in fish shell?

5 Answers5