Question

I am running scripts on a remote server from a local server via SSH. The script gets copied over using SCP in a first place, then called while being passed some arguments as follows:

scp /path/to/script server.example.org:/another/path/

ssh server.example.org \
MYVAR1=1 \
MYVAR2=2 \
/another/path/script

This works fine and on the remote server, the variables MYVAR1 and MYVAR2 are available with their corresponding value.

The issue is that these scripts are in constant development which requires the SSH command to be changed every-time a variable is renamed, added, or removed.

I’m looking for a way of passing all the local environment variables to the remote script (since MYVAR1 and MYVAR2 are actually local environment variables) which would address the SSH command maintenance issue.

Since MYVAR1=1 \ and MYVAR1=1 \ are lines which follow the env command output I tried replacing them with the actual command as follows:

ssh server.example.org \
`env`
/another/path/script

This seems to work for “simple” env output lines (e.g. SHELL=/bin/bash or LOGNAME=sysadmin), however I get errors for more “complex” output lines (e.g. LS_COLORS=rs=0:di=01;34:ln=01;[...] which gives errors such as -bash: 34:ln=01: command not found ). I can get rid of these errors by unsetting the variables corresponding to those complex output lines before running the SSH command (e.g. unset LS_COLORS, then ssh [...]) however I don’t find this very solution very reliable.

Q: Does anybody know how to pass all the local environment variables to a remote script via SSH?

PS: the local environment variables are not environment variables available on the remote machine so I cannot use this solution.

Update with solution

I ended using sed to format the env command output from VAR=VALUE to VAR="VALUE" (and concatenating all lines in to 1) which prevents bash from interpreting some of the output as commands and fixes my problem.

ssh server.example.org \
`env | sed 's/\([^=]*\)=\(.*\)/\1="\2"/' | tr '\n' ' '` \
"/another/path/script"

Answer 1

I happened to read the sshd_config man page unrelated to this and found the option AcceptEnv:

AcceptEnv
Specifies what environment variables sent by the client
will be
copied into the session’s environ(7). See SendEnv in
ssh_config(5) for how to configure the client. Note that
envi-
ronment passing is only supported for protocol 2.
Variables are
specified by name, which may contain the wildcard
characters *'
and?’. Multiple environment variables may be separated
by
whitespace or spread across multiple AcceptEnv directives.
Be
warned that some environment variables could be used to
bypass
restricted user environments. For this reason, care
should be
taken in the use of this directive. The default is not to
accept
any environment variables.

Maybe you could use this with AcceptEnv: *? I haven’t got a box with sshd handy, but try it out!