使用Expect自动执行管道命令

Question

I want to automate a piped command cat ~/.ssh/id_rsa.pub | ssh root@host 'cat >> .ssh/authorized_keys' cat ~/.ssh/id_rsa.pub | ssh root@host 'cat >> .ssh/authorized_keys' in expect . When using spawn command to execute the command,

spawn cat ~/.ssh/id_rsa.pub | ssh root@host 'cat >> .ssh/authorized_keys' 

it throws error msg,

cat |: No such file or directory
cat ssh: No such file or directory
...

How should I spawn the piped commands?

Answer 1

Because you want to technically execute multiple shell commands in one hit (and spawn doesn't handle the piped I/O), you need to encapsulate them in a script then use spawn to execute the script.

The script you want already exists as ssh-copy-id, however if you want a trimmed down version you can create a script file on the fly then pass that into expect spawn:

cat > /tmp/sshkeycopy.sh <<MYEOF
cat ~/.ssh/id_rsa.pub | ssh user@host 'mkdir -p -m 600 ~/.ssh; cat >> ~/.ssh/authorized_keys'
MYEOF

chmod u+x /tmp/sshkeycopy.sh

expect -c "
spawn /tmp/sshkeycopy.sh
expect { ... }"

With this bash example, the shell will handle the pipe as expected and just throw the password prompt out for expect to handle.

Answer 2

Does spawn handle input redirection?

spawn ssh root@host "cat >> .ssh/authorized_keys" < ~/.ssh/id_rsa.pub

Input redirection would be preferred over using cat with a single file if you weren't using expect .

Edit: use double quotes around cat command, instead of single quote (which does not work, as tested)

Answer 3

您可以使用以下模式：

spawn bash -c "cat MEH | ssh root@host 'cat >>HMM' " 

Answer 4

This has been tested and works on Linux

#!/usr/bin/expect -f
set DOMAIN www.somedomain.tld
set TARFILE "[exec bash -c "echo $DOMAIN | cut -d'.' -f 1"].cert.tar"
puts "$TARFILE\r"