Expect command in bash script

Question

I meet problem with executing expect command with bash variable. I have location given by parameter of the script and I need to use it in send command via expect -c. But I need to give it with " so actually send command is thinking that I've ended typing and is recognizing rest of command as extra characters after close-quote. Thing is like:

#!/bin/bash

SIGN=ppp

expect -cd 'spawn ssh user@host
            expect "Password:"
            send -- "pass\r"
            expect "*~>"
            send -- "find /local/"$SIGN"/ -maxdepth 1 -type d -mtime +30 |xargs rm -rfv\r"
            expect "*~>"
            send -- "exit\r"'

Any idea how to send the variable from bash to expect without double-quotes? BTW - I cannot use keys for ssh

score 1 · Accepted Answer · answered Jun 20 '14 at 13:08

You can escape like that '"$SIGN"':

ex:

#!/bin/bash

SIGN=ppp

expect  -c 'spawn ssh tiago@localhost
            expect "password:"
            send -- "mypass\r"
            expect "~"
            send -- "echo '"$SIGN"'\r"
            expect "^ppp"
            send -- "exit\r"'

score 0 · Answer 2 · answered Jun 20 '14 at 12:38

0

What happens if you simply remove the "s around $SIGN?

send -- "find /local/$SIGN/ -maxdepth 1 -type d -mtime +30 |xargs rm -rfv\r"

alternatively try using {} around it.

send -- "find /local/${SIGN}/ -maxdepth 1 -type d -mtime +30 |xargs rm -rfv\r"

answered Jun 20 '14 at 12:38

Robert Ekendahl

277
2
11

Without it, it's not considering it as variable: can't read "SIGN": no such variable. the same with {} – jester2580 Jun 20 '14 at 12:46
Weird. I think it's because it's inside the `''` from the first line. Can you send them as a number of expect commands. One per line and skip the ''s? I'm sure there is a better way but that's where I would start – Robert Ekendahl Jun 20 '14 at 12:50
I actually don't get it. A number of expect commands? Won't it break ssh session? Could You give me a hint? :) I'm actually not familiar with expect at all – jester2580 Jun 20 '14 at 12:56
I'm not familiar with expect either. I was just looking at the bash syntax. I think the issue is the use of single quotes to contain the whole string. Take a look at this link http://stackoverflow.com/a/9420853/3757019. Not sure what the answer is but I think you need to use `"` instead if `'` – Robert Ekendahl Jun 20 '14 at 13:00

score 0 · Answer 3 · answered Jun 20 '14 at 14:42

You could put that variable in the environment:

export SIGN=ppp

expect -cd '
    spawn ssh user@host
    expect "Password:"
    send -- "pass\r"
    expect "*~>"
    send -- "find /local/$env(SIGN)/ -maxdepth 1 -type d -mtime +30 |xargs rm -rfv\r"
    # ...................^^^^^^^^^^
    expect "*~>"
    send -- "exit\r"
'

score 0 · Answer 4 · answered Jun 23 '14 at 09:34

I've faced one more problem: send -- "find /local/'"$SIGN"'/ -maxdepth 1 -type d -mtime +30 |grep -v '"$FILTER"' |xargs rm -rfv\r" This command is not executing. At least it's putting variables values correctly. But there is probably problem sending list of the folders to rm by xargs?

Expect command in bash script

4 Answers4