如何在bash脚本中将参数传递给内联期望？

Question

I'm creating a shell script to automate the installation of a software which has it's own installer script, but I don't want prompts to the user. So I'm using expect to answer to said script. Right now I have the following:

expect $package -c 'set timeout -1
set package [lindex $argv 0]
spawn sh install_pipeline
expect "Where should I install the software packages ? *"
send "/usr/local/$package\r"
expect "Where should I install the pipeline calibration files ? *"
send "/usr/local/$package\r"
expect eof'

Where package is a variable containing the name of the module to be installed. The problem is, this script doesn't work and prints a message saying: "Couldnt read file "name of the package": no such file or directory.

How can I pass my variable to the expect script? I don't want to create a separate script for expect to keep things simple.

Answer 1

Your expect command is surrounded with single quotes. Variables inside can not be expanded by the shell.

Try this :

expect "$package" -c "set timeout -1
set package [lindex $argv 0]
spawn sh install_pipeline
expect \"Where should I install the software packages ? *\"
send \"/usr/local/$package\r\"
expect \"Where should I install the pipeline calibration files ? *\"
send \"/usr/local/$package\r\"
expect eof"

Or if you want to keep your single quotes :

expect "$package" -c 'set timeout -1
set package [lindex $argv 0]
spawn sh install_pipeline
expect "Where should I install the software packages ? *"
send "/usr/local/'"$package"'\r"
expect "Where should I install the pipeline calibration files ? *"
send "/usr/local/'"$package"'\r"
expect eof'

Answer 2

Based on Kenavoz answer, I found the solution. As he stated, my code was encased by simple quotes, so expect couldn't get the variables from the main script. As such, putting it with only normal quotes solved the problem, without the need to pass the variable as an argument:

expect -c "set timeout -1
spawn sh install_pipeline
expect \"Where should I install the software packages ? *\"
send \"/usr/local/$package\r\"
expect \"Where should I install the pipeline calibration files ? *\"
send \"/usr/local/$package\r\"
expect eof"

Answer 3

You could pass it in through the environment:

env pkg="$package" expect -c '
    set timeout -1
    spawn sh install_pipeline
    expect "Where should I install the software packages ? *"
    send "/usr/local/$env(pkg)\r"
    expect "Where should I install the pipeline calibration files ? *"
    send "/usr/local/$env(pkg)\r"
    expect eof
'