ssh remotecluster 'bash -s' << EOF
> export TEST="sdfsd"
> echo $TEST
> EOF
This prints nothing.
Also it still does not work even if I store the variable into file and copy it to remote.
TEST="sdfsdf"
echo $TEST > temp.par
scp temp.par remotecluster
ssh remotecluster 'bash -s' << EOF
> export test2=`cat temp.par`
> echo $test2
> EOF
Still prints nothing.
So my question is how to pass local variable to the remote machine as a variable ?
Answers have been give in this
The variable assignment TEST="sdfsd" given in the here document is no real variable assignment, i. e. the variable assignment will actually not be performed directly in the declaration / definition of the here document (but later when the here document gets evaluated by a shell).
In addition, the $TEST variable contained in an unescaped or unquoted here document will be expanded by the local shell before the local shell executes the ssh command.
The result is that $TEST will get resolved to the empty string if it is not defined in the local shell before the ssh command or the here document respectively.
As a result, the variable assignment export TEST="sdfsd" in the here document will not take effect in the local shell, but first be sent to the shell of the remote host and only there be expanded, hence your prints nothing experience.
The solution is to use an escaped or single-quoted here document, <<\EOF or <<'EOF'; or only escape the \$TEST variable in the here document; or just define the $TEST variable before the ssh command (and here document).
# prints sdfsd
export TEST="sdfsd"
ssh localhost 'bash -s' << EOF
echo $TEST
EOF
# prints sdfsd
ssh localhost 'bash -s' << EOF
export TEST="sdfsd"
echo \$TEST
EOF
# prints sdfsd
ssh localhost 'bash -s' <<'EOF'
export TEST="sdfsd"
echo $TEST
EOF
I know this is old but I want to add my two cents to this in case anyone's not familiar with here docs. I just want to add to Carlo's post, with the heredoc add the variable with the ssh session and maybe do the quotes differently:
TEST="sdfsd"
ssh remotehost bash -s "$TEST" <<-'HEREDOC'
export $1
echo $1
HEREDOC
Most people want to change a variable and not hard code it in the heredoc, I find that works for me usually, but someone should verify. Also mind the "tabs" if you used <<-, and avoid spaces. Spaces always get me, so tab over. If it fails, take out the dash and tabs.
export variable, ssh send exported(environment) variables to server export VAR=test ssh -v 127.0.0.1 echo $VAR test above commands and see result
