Append to a file repeating output

Shell Programming and Scripting
1

Hello,

i'm trying to force a command to read every second from an interface

watch  -n1 (command) /dev/x | cat  >> output

but it continue to overwrite the file, without append the content

Thanks and advace for help as usual

regards

2

What does command do to the output file? You know that that cat is unnecessary?

3

hello,

just write 4 columns of raw data, like a timestamp and numbers. Yes i've tried also without it and without the pipe using just >> , again still the same.

Thank you

4

So - why did you put it back in?

watch seems to do funny things to your output file, e.g. writing many console code/control chars. You should have seen it grow during operation.

5

Place the whole command to watch within single coma.

watch  -n1 'command /dev/x | cat  >> output'

However, the command cat it not necessary there.

watch  -n1 'command /dev/x >> output'
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