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expect MacOS Command Guide

The MacOS expect command allows users to automate interactive processes by scripting expected responses. This powerful tool can streamline repetitive tasks and improve workflow efficiency. With expect, users can create scripts to interact with other programs, handle password prompts, and automate complex tasks. By specifying expected responses and actions, users can effectively automate interactive processes and save time. Familiarizing yourself with the MacOS expect command can greatly enhance your productivity and efficiency on your Mac.

Terminal window
expect [-dDeinNrtTuv] [-d #] [-f file] [-k name] [-p passwd] [-P flag] [-l var] [user[@host]]
OptionDescription
-dRun in debug mode
-DEnable debugging output
-eExecute the commands given as input
-iIgnore case when matching patterns
-nExit if end of file is reached
-NExit if an end-of-file condition is encountered
-rDisable flow control
-tEnable timing output
-TSet timeout for input to seconds
-uDisable timestamps in logging output
-vPrint information about what is going on
-d #Set debug level to #
-f fileRead commands from file
-k nameSpecify a key for use in scripts
-p passwdProvide the password
-P flagSet a public key flag
-l varLog result of the operation in variable var
user[@host]The user and host to connect to

There are no specific parameters for the expect command.

SSH into a Server using Password Authentication

Section titled “SSH into a Server using Password Authentication”
Terminal window
expect -c 'spawn ssh user@hostname ; expect "password:" ; send "your_password\r" ; interact'

Logs into a remote server using an SSH connection with password authentication.

Automate Software Installation with Expect

Section titled “Automate Software Installation with Expect”
Terminal window
expect -c 'spawn ./install_script.sh ; expect "Do you want to continue? (y/n)" ; send "y\r" ; interact'

Automates the installation of software by interacting with the install script.

Terminal window
expect -c 'spawn tail -f logfile.log ; expect "error" { puts "Error detected!" }'

Monitors a log file in real-time and triggers an action if the specified keyword “error” is detected.

Interactive File Transfer with SCP and Expect

Section titled “Interactive File Transfer with SCP and Expect”
Terminal window
expect -c 'spawn scp file.txt user@hostname:/path/to/destination ; expect "password:" ; send "your_password\r" ; interact'

Transfers a file using SCP while providing the password interactively through the Expect command.

Terminal window
expect -c 'spawn ftp ftp.example.com ; expect "Name" ; send "username\r" ; expect "Password" ; send "your_password\r" ; interact'

Automates FTP login by providing the username and password interactively through Expect.

Terminal window
expect -c 'spawn ./interactive_script.sh ; expect "Enter username:" ; send "user\r" ; expect "Enter password:" ; send "pass\r" ; interact'

Handles multiple user inputs during the execution of a script by sending responses using the Expect command.

Expect for Automated System Administration Tasks

Section titled “Expect for Automated System Administration Tasks”
Terminal window
expect -c 'spawn sudo usermod -aG wheel new_user ; expect "assword for" {send "admin_password\r"} ; interact'

Automates the process of adding a user to the “wheel” group by providing the necessary password via Expect.

To install the expect command in MacOS, run the following command:

Terminal window
brew install expect

The expect command in MacOS is used for automating interactive applications. It allows you to send specific responses to prompts during the execution of scripts.

How do I create an expect script in MacOS?

Section titled “How do I create an expect script in MacOS?”

To create an expect script in MacOS, you can use a text editor to write the script with the necessary commands and responses. Save the file with a .exp extension and make it executable using the chmod command.

To run an expect script in MacOS, use the following command:

Terminal window
expect script.exp

Can I use expect to automate SSH connections in MacOS?

Section titled “Can I use expect to automate SSH connections in MacOS?”

Yes, you can use the expect command in MacOS to automate SSH connections. You can write an expect script to handle the SSH prompts, such as providing a password automatically.

How do I pass arguments to an expect script in MacOS?

Section titled “How do I pass arguments to an expect script in MacOS?”

To pass arguments to an expect script in MacOS, you can use the $argv array. Here’s an example of how to access arguments in an expect script:

Terminal window
set username [lindex $argv 0]
set password [lindex $argv 1]
  • Automating interactive command line applications
  • Scripting SSH and SCP sessions
  • Testing interactive programs
  • Setting up automated backups
  • Automating software installations
  • Creating self-updating scripts
  • Interacting with various network devices