CODEWITHSUNDEEP
bashgrep
mahmood
mahmood

Reputation: 24795

online grep while generating output

I want to run a program which writes some outputs to a file. Now in this file, I will grep for certain strings and write them to another file. I don't want to serialize the process. Instead I want to pipe the commands. However this command doesn't work

./run_prog | grep READ > read_data.txt

Upvotes: 0

Views: 157

Answers (2)

Magnus
Magnus

Reputation: 11466

As already mentioned, sounds like your program might be writing to STDERR instead of STDOUT. To make sure you capture that as well, try this:

./run_prog 2>&1 | grep READ > read_data.txt

Upvotes: 1

hol
hol

Reputation: 8423

Make sure your ./run_prog gives your output to STDOUT. The following example shows that it should work.

$>echo "READ" | grep READ > read_data.txt
$>cat read_data.txt
READ
$>

Since you are now assured it should work debug by just running ./run_prog then add | grep.

Upvotes: 1

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