# How to "source" a file?

**URL:** <https://www.ruby-forum.com/t/how-to-source-a-file/173377>\
**Category:** Ruby\
**Created:** [August 7, 2009, 4:48pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377 "2009-08-07T16:48:15Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 7, 2009, 4:48pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/1 "2009-08-07T16:48:15Z")

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I have a bash file ~/.myenv that contains environmental variables like:

export EDITOR=vi  
export FOO=bar  
…

How do I source this file from within a ruby script that starts like?

#!/usr/bin/ruby

I could source the file in bash before running the ruby script, but I  
prefer that the script do it, in case the user forgets.

Thx.

-Ken

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 7, 2009, 5:00pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/2 "2009-08-07T17:00:30Z")

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Ken Feng wrote:

> I have a bash file ~/.myenv that contains environmental variables like:
> 
> export EDITOR=vi  
> export FOO=bar  
> …
> 
> How do I source this file from within a ruby script that starts like?
> 
> #!/usr/bin/ruby
> 
> I could source the file in bash before running the ruby script, but I  
> prefer that the script do it, in case the user forgets.
> 
> Thx.
> 
> -Ken

`source ~/.myenv`

at work… NOT TESTED… guess

ilan

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 7, 2009, 6:06pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/3 "2009-08-07T18:06:04Z")

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On Aug 7, 2009, at 11:00 AM, Ilan B. wrote:

> > #!/usr/bin/ruby  
> > at work… NOT TESTED… guess
> 
> ilan

Nope! That will set those variables in the child process and any of  
its children, but they’ll go away and have no effect on your ruby  
process.

Your best bet is to warn the user if you are using defaults and tell  
him/her/yourself to fix it.

unless ENV[‘EDITOR’]  
ENV[‘EDITOR’] = ‘vi’  
puts “Environment has no EDITOR using ‘#{ENV[‘EDITOR’]}’”  
puts “Did you mean to?: source ~/.myenv”  
end

You could also exit without doing anything if the value has no  
acceptable default.

-Rob

Rob B. [http://agileconsultingllc.com](http://agileconsultingllc.com)  
removed\_email\_address@domain.invalid

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 7, 2009, 8:55pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/4 "2009-08-07T20:55:51Z")

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At 2009-08-07 10:48AM, “Ken Feng” wrote:

> I have a bash file ~/.myenv that contains environmental variables like:
> 
> export EDITOR=vi  
> export FOO=bar  
> …

Since Ruby is not Bash, you have to parse the file:

```
File.foreach("myenv") do |line|
  line.chomp.scan(/^export (.+?)=(.*)$/) do |name, val|
    ENV[name] = val
  end
end

p ENV['FOO'] # => "bar"
```

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 8, 2009, 12:56am UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/5 "2009-08-08T00:56:28Z")

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On Friday 07 August 2009 02:55:11 pm Glenn J. wrote:

> Since Ruby is not Bash, you have to parse the file:
> 
> ```
> File.foreach("myenv") do |line|
> line.chomp.scan(/^export (.+?)=(.*)$/) do |name, val|
> ENV[name] = val
> end
> end
> 
> p ENV['FOO'] # => "bar"
> 
> ```

That’s pretty fragile – it would severely limit what you can put in the  
file.

There are a few ways of doing this, depending on your goal. One would be  
to  
run a bash (or better yet, sh) script as a wrapper around your Ruby  
script –  
that is, if your command is installed as /usr/local/bin/foo, have it be  
a  
shell script which does this:

#!/bin/sh  
. ~/.myenv  
exec /usr/lib/foo/foo.rb $@

Another hack I’ve used, when I wasn’t sure whether or not I’d need those  
variables, is to have bash execute the file, and then tell me. If you  
only need  
one variable, this is easy:

ENV[‘FOO’] = `source ~/.myenv && echo -n $FOO`

If you wanted all of the variables, here’s one (clumsy) way to do it  
without  
having to (really) parse anything:

require ‘yaml’  
s = `source ~/.myenv && ruby -e 'require "yaml"; print ENV.to_hash.to_yaml`  
Yaml.load(s).each\_pair{|k,v| ENV[k]=v}

I realize I could’ve made that less ugly, but I’m not sure there’s a  
good way  
to make it pretty. It’s essentially the same as extracting a single  
variable,  
except that it invokes another Ruby interpreter to dump the entire  
environment  
as a yaml stream. I did this because it’s a lot easier to just throw the  
yaml  
parser at the problem than try to parse the output of something like  
‘env’ –  
I couldn’t even figure out which environment variables existed,  
otherwise.

About the only way I could “improve” it is by streaming that Yaml  
generation/parsing, but if anyone has an environment big enough for it  
to  
matter, they’ve already got problems.

One final way would be to add a ‘source ~/.myfile’ to any other programs  
you try  
to run – since you mentioned EDITOR, I’m assuming that’s why.

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 10, 2009, 7:26pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/6 "2009-08-10T19:26:01Z")

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Den 10 Aug 2009 16:57:42 GMT skrev Glenn J.:

> > > ```
> > > p ENV['FOO'] # => "bar"
> > > 
> > > ```
> 
> But it’s not going to get tripped up by any line that doesn’t match the  
> pattern. It won’t run off and execute any of the other commands in this  
> bash file.
> 
> I’m not personally offended by your comments, I’m curious to learn more.

A couple of lines from my .profile:

export PATH=${HOME}/bin:${PATH}  
source ${HOME}/.bashrc  
if [-z “$COLORTERM”]  
then  
export EDITOR=vi  
fi

/Kent

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**Author:** ![kfmfe04](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/71c47a/32.png) [@kfmfe04](https://www.ruby-forum.com/u/kfmfe04)\
**Post date:** [August 10, 2009, 7:01pm UTC](https://www.ruby-forum.com/t/how-to-source-a-file/173377/7 "2009-08-10T19:01:26Z")

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At 2009-08-07 06:53PM, “David M.” wrote:

> That’s pretty fragile – it would severely limit what you can put in  
> the file.

I don’t understand this comment. How is it “severely limiting”?

Granted, it won’t properly parse  
export a=b c=d e=f foo bar  
and I didn’t account for extra whitespace. The OP didn’t specify any  
such requirements though.

But it’s not going to get tripped up by any line that doesn’t match the  
pattern. It won’t run off and execute any of the other commands in this  
bash file.

I’m not personally offended by your comments, I’m curious to learn more.