Drop special character from piped value

[Superdude_123]

I'm trying to drop the character ^M from my piped command, however, I can't seem to get it to drop.

In one terminal window, I am running

echo -en "adc read 0\r"  > /dev/ttyACM0

which makes my device send back some results with numbers to the same port. To read the returned value, I am in a separate window I am running

cat -v < /dev/ttyACM0 | grep -v ">"

function that is already cleaning up some of the results, but still allowing ^M to come back. I have tried dropping all but numbers by expanding my cat to

cat -v < /dev/ttyACM0 | grep -v ">" | tr -dc '[:alnum:]'

, but no luck.

I'm open to ideas on how to drop the two characters that I don't want to see.

[spjackson]

Simply

cat -v < /dev/ttyACM0 | grep -v ">" | tr -d '\r'

will drop the carriage returns. Which other character are you wanting to drop?

[Superdude_123]

That just got me some blank results.

If I wanted to filter the character ^ and the letter M out, how could that be done?

[steeldriver]

If you don't want carriage returns to be displayed as ^M, don't add the -v to the cat

cat < /dev/ttyACM0 | grep -v ">" | tr -d '\r'

If you want to keep the -v for some reason, then you will need to treat ^M as literal characters e.g.

cat -v < /dev/ttyACM0 | grep -v ">" | sed 's/\^M$//'