CODEWITHSUNDEEP
linuxbashubunturbenv
Godzilla74
Godzilla74

Reputation: 2502

source /etc/profile within bash script

I have a bash script that installs rbenv to /usr/local and adds the required environment variables to /etc/profile. My user is root:

#!/bin/bash

exec {log_fd}>log.txt

git clone https://github.com/rbenv/rbenv.git /usr/local/rbenv >&$log_fd 2>&1
git clone https://github.com/rbenv/ruby-build.git /usr/local/rbenv/plugins/ruby-build >&$log_fd 2>&1
echo 'export RBENV_ROOT=/usr/local/rbenv' >> /etc/profile >&$log_fd 2>&1
echo 'export PATH="/usr/local/rbenv/bin:$PATH"' >> /etc/profile >&$log_fd 2>&1
echo 'if which rbenv > /dev/null; then eval "$(rbenv init - --no-rehash)"; fi' >> /etc/profile >&$log_fd 2>&1
. /etc/profile

However, the PATH variable isn't being exported as it should, but RBENV_ROOT is!

~#: printenv
RBENV_ROOT=/usr/local/rbenv
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
MAIL=/var/mail/root
LANG=en_US.UTF-8
RBENV_SHELL=bash

I would expect to see /usr/local/rbenv/ as part of the PATH, right?

I've also tried switching up the syntax for adding the path but that didn't help either:

echo 'export PATH=$PATH:/usr/local/rbenv/bin' >> /etc/profile 2>&1

In case you're wondering, I'm redirecting the output because this is all within a whiptail menu.

So, why would one variable be shown RBENV_ROOT but not my supposedly updated PATH ?

Upvotes: 1

Views: 1607

Answers (1)

Matei David
Matei David

Reputation: 2362

The sequence >>/etc/profile >&$log_fd 2>&1 causes the echo to run with stdout and stderr redirected to file descriptor $log_fd, not to /etc/profile. That's because the redirections are processed left-to-right in this case, and the second overwrites the first when it comes to stdout. To see this:

#!/bin/bash
exec {fd}>/tmp/file1
echo 'hello' >>/tmp/file2 >&$fd 2>&1

Make this executable, run it, then check that hello appears only in /tmp/file1.

Of course, this doesn't explain why RBENV_ROOT is set. Perhaps you set it in some other startup file?

As for using echo 'export PATH=$PATH:/usr/local/rbenv/bin' >>/etc/profile', I can confirm that if I do that on Ubuntu 14.04, I see the new dir as part of PATH, as expected. However, to see the change, you must make sure /etc/profile gets sourced, which only happens if you start a login shell. E.g., env -i bash -lc 'echo $PATH'.

Upvotes: 2

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