Thursday, November 18, 2021

[SOLVED] Combine two grep commands to process input from a file or grep lines starting with one specific substring and contain another after

Issue

I have a file that i want to pars using grep command, the file consist of lines like this:

NVO,0,267,61,247357,247357,O,19:00:00.000000,06:09:08.417320,07:55:22.068670
DVD,0,267,61,247357,247357,O,19:00:00.000000,06:09:08.417320,07:55:22.068670
NVO,0,267,61,247358,247358,B,19:00:00.000000,06:09:08.417407,07:55:22.079291
DVD,0,267,61,247358,247358,B,19:00:00.000000,06:09:08.417407,07:55:22.079291

I want to get only the line that start with NVO, and have ,B, in the line. the out put should look like this:

NVO,0,267,61,247358,247358,B,19:00:00.000000,06:09:08.417407,07:55:22.079291

to get the NVO, line I'm using grep ^NVO, file_name.txt but I'm unable to add the second condition ,B, I tried grep '^NVO,|,B,' file_name.txt and also

grep ",B," | grep "^NVO," file_name.txt

with no luck I know I can do it with two commands, the first to write to file and then to do a second grep command with the ,B, filter


Solution

The operation you're attempting does not actually require combining two grep calls. Therefore, you can use

grep "^NVO,.*,B," file > outfile

Details:

  • ^ - string start
  • NVO, - an NVO, string
  • .* - any text (any zero or more chars)
  • ,B, - a ,B, text.

See the online demo:

#!/bin/bash
s='NVO,0,267,61,247357,247357,O,19:00:00.000000,06:09:08.417320,07:55:22.068670
DVD,0,267,61,247357,247357,O,19:00:00.000000,06:09:08.417320,07:55:22.068670
NVO,0,267,61,247358,247358,B,19:00:00.000000,06:09:08.417407,07:55:22.079291
DVD,0,267,61,247358,247358,B,19:00:00.000000,06:09:08.417407,07:55:22.079291'
grep "^NVO,.*,B," <<< "$s"

Output:

NVO,0,267,61,247358,247358,B,19:00:00.000000,06:09:08.417407,07:55:22.079291


Answered By - Wiktor Stribiżew
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