Question

7

Filter terminal command to text file

rated 0 times [ 7] [ 0] / answers: 1 / hits: 4727 / 3 Years ago, tue, october 5, 2021, 7:00:33

Problem: I have dmesg | grep ttyUSB command that has the following output:

[    7.648896] usb 1-2: GSM modem (1-port) converter now attached to ttyUSB0

[    7.649091] usb 1-2: GSM modem (1-port) converter now attached to ttyUSB1

[    7.649502] usb 1-2: GSM modem (1-port) converter now attached to ttyUSB2

[17406.327030] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0

[17406.329670] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1

[17406.334036] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2

[90128.405694] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB0

[90128.405987] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB1

[90128.406295] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB2

[90132.905458] usb 1-2: GSM modem (1-port) converter now attached to ttyUSB3

[90132.905791] usb 1-2: GSM modem (1-port) converter now attached to ttyUSB4

[90132.906541] usb 1-2: GSM modem (1-port) converter now attached to ttyUSB5

[90148.661532] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB6

[90148.661828] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB7

[90148.662440] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB8

need to redirect this output to a text file, I am using the following command for this:

dmesg | grep ttyUSB > test.txt

Everything works fine, but I need only list the available ports. I wish the text file output to be like this:

ttyUSB0 

ttyUSB1 

ttyUSB2 

ttyUSB3

How can I do this?

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eryeath

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2 Years ago

answered 3 Years ago ampust · Accepted Answer

Just use this command:

dmesg | egrep -o "ttyUSB[0-9]+" | sort -u > test.txt

It will match and return the ttyUSB patterns.

From man grep:

   -o, --only-matching

          Print only the matched (non-empty) parts of a matching line,

          with each such part on a separate output line.