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Top Forums Shell Programming and Scripting Assigning variable to output gives error with expected result Post 302983367 by baris35 on Monday 10th of October 2016 04:42:50 PM
Old 10-10-2016
Assigning variable to output gives error with expected result

Hello,
I am trying to print out the first string matching query with grep and I need your help.

My scenario:

Database
Code:
John F 
4433 Street No 88 CA
Elisabeth Taylor
7733 Street No 26 ON
Jack Nicholson
0133 Green Park No 34 AR
John F 2
9399 Southpark No 02D UT

test.sh
Code:
#!/bin/bash
A="$(cat Database | grep "$1" -A1 | tail -n 1)"
printf "$A"

When I run
Code:
./test.sh John F

, it prints out the second John F.
How can I print the first one and how come can I make it searching accurately?

The most importan question is:
What would happen if I simultaneously and continuously run this script at the background with different search queries ( ten or twenty script.sh processes will be running I mean), do you think that $A will be confused and will give wrong answers?

I'd appreciate if you could give an answer to solve this or lead me to right direction.

Thanks in advance
Boris


Moderator's Comments:
Mod Comment Please use CODE tags correctly as required by forum rules!

Last edited by RudiC; 10-10-2016 at 05:57 PM.. Reason: Added CODE tags.
 

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RAKE(1) 						 Ruby Programmers Reference Guide						   RAKE(1)

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rake -- Ruby Make SYNOPSIS
rake [--f Rakefile] [--version] [-CGNPgnqstv] [-D [PATTERN]] [-E CODE] [-I LIBDIR] [-R RAKELIBDIR] [-T [PATTERN]] [-e CODE] [-p CODE] [-r MODULE] [--rules] [variable=value] target ... DESCRIPTION
Rake is a simple ruby(1) build program with capabilities similar to the regular make(1) command. Rake has the following features: o Rakefiles (Rake's version of Makefiles) are completely defined in standard Ruby syntax. No XML files to edit. No quirky Makefile syntax to worry about (is that a tab or a space?). o Users can specify tasks with prerequisites. o Rake supports rule patterns to synthesize implicit tasks. o Flexible FileLists that act like arrays but know about manipulating file names and paths. o A library of prepackaged tasks to make building rakefiles easier. OPTIONS
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