chat

Execute a chat script directly

$ chat '[expect_send_pairs]'

$ chat -f '[path/to/chat_script]'

$ chat -t [timeout_in_seconds] '[expect_send_pairs]'

$ chat -v '[expect_send_pairs]'

$ chat -r [path/to/report_file] '[expect_send_pairs]'

$ chat -T '[phone_number]' '"ATDT\\T CONNECT"'

$ chat 'ABORT "[error_string]" [expect_send_pairs]'

chat [options] script

chat automates conversations with modems and serial devices by exchanging expect-send string pairs. It waits for an expected string from the device, then sends a response, repeating this process through a scripted sequence.
The primary use case is establishing PPP (Point-to-Point Protocol) connections over serial lines and modems. A typical chat script initializes the modem with AT commands, dials a phone number, waits for a CONNECT response, and handles login sequences. Abort strings can be defined to terminate the script on error conditions like BUSY or NO CARRIER.
chat is part of the ppp package and is typically invoked by pppd rather than run directly. Scripts can be specified inline on the command line or loaded from a file.

-f file

Read script from file

Timeout for expecting responses

Verbose logging to syslog

Log specific strings to report file

Substitute \T in script with string

Log all conversation to stderr

ABORT string

Abort if string is received

Set timeout for next expect

Log string to report file

Primarily used for legacy modem/PPP connections. Timing is critical; adjust timeouts for slow devices. Escape sequences may need proper quoting.

pppd(8), expect(1)