Linuix users? any idea on why i cant save stdout to file?

[rizla420]

Im trying to log serial data coming from the arduino and saving it to a file after i use grep to remove empty lines with this expression

cat /dev/ttyUSB0 | grep .

Typically if you want to write to a file you'd simply use the '>' character and specify the file to save to, like so:

cat /dev/ttyUSB0 | grep . > log.txt

for some reason, nothing is being written to the file. Any ideas on the proper way to pipe the grep output to a file?

There def is data coming from the serial port, just not being saved when piped to file..

[mtbf0]

you getting the data on your console with cat /dev/ttyUSB0 | grep .?

[rizla420]

you getting the data on your console with cat /dev/ttyUSB0 | grep .?

yup, i've broken it up into steps to debug it.

so, cat /dev/ttyUSB0 basically shows all the data streaming realtime with the extra blank lines i'm trying to strip with grep.

next when i through the grep into the chain

cat /dev/ttyUSB0 | grep .

the output still streams as it should, but in the new format that i want. I just cant save the output to a log file for whatever reason.

I though it was the . after grep but i put it in "." and it still works, but didnt allow me to save.

cat /dev/ttyUSB0 | grep "."

[mtbf0]

how are you stopping the command? is the arduino sending an eof? you killing it with a ^c?

[rizla420]

how are you stopping the command? is the arduino sending an eof? you killing it with a ^c?

i'm killing it with control-c . I thought using cat would have been the best because it will read it the whole time.

[mtbf0]

might let it run for awhile so the buffers can fill up and get dumped to disk.

[mwr]

This post at Arduino.cc may help with buffering.