How do I set $PATH such that `ssh user@host command` works?

Question

I can't seem to set a new $PATH such that it is used when executing commands via ssh user@host command. I have tried adding export PATH=$PATH:$HOME/new_path to ~/.bashrc and ~/.profile on the remote machine, but executing ssh user@host "echo \$PATH" shows that the change has not been picked up (it shows /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games). The remote machine is running Ubuntu 8.04.

I'm sure I could hack it into /etc/profile, but that's not a clean solution and it only works when one has root access.

Solution 1

As grawity said, ~/.bashrc is what you want, since it is sourced by non-interactive non-login shells.

I expect the problem you're having has to do with the default Ubuntu ~/.bashrc file. It usually starts with something like this:

# If not running interactively, don't do anything
[ -z "$PS1" ] && return

You want to put anything for non-interactive shells before this line.

Solution 2

Do you have an ~/.bash_login or ~/.bash_profile?

Bash in interactive mode checks for these files, and uses the first existing one, in this order:

1. ~/.bash_profile
2. ~/.bash_login
3. ~/.profile

So if you have an ~/.bash_profile, then whatever changes you do to ~/.profile will be left unseen.

Bash in non-interactive mode sometimes reads the file ~/.bashrc (which is also often source'd from the interactive scripts.) By "sometimes" I mean that it is distribution-dependent: quite oddly, there is a compile-time option for enabling this. Debian enables the ~/.bashrc reading, while e.g. Arch does not.

ssh seems to be using the non-interactive mode, so ~/.bashrc should be enough. When having problems like this, I usually add a few echo's to see what files are being run.

Solution 3

ssh documentation says:

If command is specified, it is executed on the remote host instead of a login shell.

which is why adding to the bashrc files doesn't work. you do however have the following options:

1. If the PermitUserEnvironment option is set in the sshd config, you can add your PATH setting to ~/.ssh/environment

2. ssh remotemachine 'bash -l -c "somecommand"'

Solution 4

You can always say:

ssh remotemachine 'export PATH=wedontneedastinkingpath; echo $PATH'

Solution 5

In addition to @signpolyma answer, you will have to add your export before these lines

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

View more solutions

Comments

[Denver Gingerich]

1. It's not set in my sshd config and man sshd_config says it's off by default so it's unlikely this solution would work for most people. 2. This would work, but I can't easily modify the command sent to ssh (see the second comment on my question).

[Denver Gingerich]

Yep, I moved the export PATH=$PATH:$HOME/new_path above that line and it worked. Thanks!

[Jess]

Adding the echos helped... but I'm still chasing down a way to execute 'ssh -X remotemachine "xterm"' and have the full system / user path from /etc/profile and ~/home/username/.bash_profile. If I source both file in the command, it works.. but its ugly : ).

[basin]

.bashrc is unreliable. man bash: "Bash attempts to determine when it is being run with its standard input connected to a network connection". This works on RHEL, but not on Archlinux. I had to edit /etc/environment to change the default PATH

[nknight]

How do you know that "Bash in non-interactive mode reads the file ~/.bashrc"? I do not see this statement in the manpage. Thanks

[nknight]

If you want a non-interactive non-login shell to source ~/.bashrc, it seems that you need to additionally set the environment variable BASH_ENV; see superuser.com/a/585699/100843 . For non-interactive login shells, you'd probably have to modify one of the three startup scripts you mentioned.

[math]

For ZSH the non-interactive file is: .zshenv

[Ronny Andersson]

This solution does not need any change on the remote machine, which is a good thing.

[Ernie S]

I actually just commented out these lines altogether - found in ~/.bashrc in Ubuntu 16.04 LTS desktop. No everything works. Also set PermitUserEnvironment to yes.

[JoL]

@math .zshenv is always sourced; it doesn't matter if it's interactive or not.

[not2savvy]

1. Does not work as expected, because in ~/.ssh/environment, you cannot add pathes to PATH, because $PATH will not be resolved.

[Mike]

You should add mention of .zshenv for zsh users, it took me quite a while to find it in the comments on other answers

[Doomd]

on MacOS Catalina, I had to put a "zshenv" file at /etc/zshenv (with my export paths).

[lindes]

@Doomd: did ~/.zshenv not work for you? It worked for me... And yes, this answer would benefit from being edited to include information for various other shells, as well (zsh, fish, ...)