I have written an bash script foo.sh
#!/usr/bin/env bash
echo "starting the script";
I want to execute it in my remote server.
I tried ssh user@remote-addr < test.sh and it worked.
After that I changed the test.sh file like this
#!/usr/bin/env bash
echo "starting the script";
echo $1;
now I want to pass a local parameter to execute with my script but when I type ssh user@remote-addr < test.sh testparam it returns an error.
How can I pass parameters with my scripts?
bash or ksh as /bin/shIf your remote /bin/sh is provided by bash or ksh, you can safely do the following with an untrusted argument list, such that even malicious names (like $(rm -rf $HOME).txt) can be passed as arguments safely:
runRemote() {
local args script
script=$1; shift
# generate eval-safe quoted version of current argument list
printf -v args '%q ' "$@"
# pass that through on the command line to bash -s
# note that $args is parsed remotely by /bin/sh, not by bash!
ssh user@remote-addr "bash -s -- $args" < "$script"
}
...thereafter:
runRemote test.sh testparam
/bin/shNote that the following still needs to be run in bash, but will work correctly when the system being ssh'd into has a /bin/sh that is POSIX-baseline, so long as the remote machine has bash installed.
To be safe against sufficiently malicious argument data (attempting to take advantage of the non-POSIX compliant quoting used by printf %q in bash when nonprintable characters are present in the string being escaped) even with a /bin/sh that is baseline-POSIX (such as dash or ash), it gets a bit more interesting:
runRemote() {
local script=$1; shift
local args
printf -v args '%q ' "$@"
ssh user@remote-addr "bash -s" <<EOF
# pass quoted arguments through for parsing by remote bash
set -- $args
# substitute literal script text into heredoc
$(< "$script")
EOF
}
Similarly invoked as:
runRemote test.sh testparam
Use the -s option, which forces bash (or any POSIX-compatible shell) to read its command from standard input, rather than from a file named by the first positional argument. All arguments are treated as parameters to the script instead.
ssh user@remote-addr 'bash -s arg' < test.sh
-- before arg so it is interpreted as an argument to test.sh instead of bash. Also, you probably want to use /usr/bin/env bash, as in the original script.
/bin/sh evaluating the command is searching for bash in the PATH even without env, no?env is not needed in this case.