use she-bang in oneliner

Question

Is it possible to use she-bang in oneliners?

I am trying to run this script from https://stackoverflow.com/questions/16928004/how-to-enter-ssh-password-using-bash, in one liner.

If I put this in a file, and run it with ./file it works as expected, but how would I be able to run that as oneliner?

This works as a script without any issues.

#!/usr/bin/expect -f
spawn ssh user@my.server.com
expect "assword:"
send "mypassword\r"
interact

How would I be able to run that from oneliner?

If I try to run

spawn ssh user@my.server.com; expect "assword:"; send "mypassword\r"; interact

it returns:

bash: spawn: command not found

If I try to run

#!/usr/bin/expect -f; spawn ssh user@my.server.com; expect "assword:"; send "mypassword\r"; interact

then the whole thing is treated as a comment and nothing happens.

EDIT:

tried running stuff suggested in answers:

expect -c `spawn ssh user@server "ls -lh /some/file"; expect "assword:"; send "mypassword\r"; interact`

it returned

bash: spawn: command not found
couldn't read file "assword:": no such file or directory
bash: send: command not found
bash: interact: command not found
expect: option requires an argument -- c

When running:

$ cat << 'EOF' | /usr/bin/expect -
> spawn ssh user@server "ls -lh file"
> expect "assword:"
> send "password\r"
> interact
> EOF

It seems to SSH to server, but doesn't run the command, or it doesn't output any result of it:

it returns:

spawn ssh user@server ls -lh file
user@server password

When I run it from script:

./test
spawn ssh user@server ls -lh file
user@server's password:
-rw-rw-r-- 1 user user 467G Jan  2 00:46 /file

EDIT2:

Issue with first command was with backtick instead of single quote, following command works as expected

expect -c 'spawn ssh user@server "ls -lh file"; expect "assword:"; send "mypassword\r"; interact'

:

Answer 1

As a one-liner, you'd pass the script as the argument to expect -c

expect -c 'spawn ssh user@my.server.com; expect "assword:"; send "mypassword\r"; interact'

Note that the shell's quotes are '...' and "...", and expect's corresponding quotes are {...} and "...", so there's some flexibility for passing shell vars and so forth.

But that quickly becomes unreadable and unmaintainable.

Answer 2

expect can read its script from the standard input:

cat << 'EOF' | /usr/bin/expect -
spawn ssh user@my.server.com
expect "assword:"
send "mypassword\r"
interact
EOF