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linuxsearchawkgrep
Ste Prescott
Ste Prescott

Reputation: 1817

Linux scripting: Search a specific column for a keyword

I have a large text file that contains multiple columns of data. I'm trying to write a script that accepts a column number and keyword from the command line and searches for any hits before displaying the entire row of any matches.

I've been trying something along the lines of:

grep $fileName | awk '{if ($'$columnNumber' == '$searchTerm') print $0;}'

But this doesn't work at all. Am I on the right lines? Thanks for any help!

Upvotes: 4

Views: 4103

Answers (2)

Steve
Steve

Reputation: 54392

The -v option can be used to pass shell variables to awk command.

The following may be what you're looking for:

awk -v s=$SEARCH -v c=$COLUMN '$c == s { print $0 }' file.txt

EDIT:

I am always trying to write more elegant and tighter code. So here's what Dennis means:

awk -v s="$search" -v c="$column" '$c == s { print $0 }' file.txt

Upvotes: 2

torek
torek

Reputation: 488193

Looks reasonable enough. Try using set -x to look at exactly what's being passed to awk. You can also use different and/or more awk things, including getting rid of the separate grep:

awk -v colnum=$columnNumber -v require="$searchTerm"
    "/$fileName/ { if (\$colnum == require) print }"

which works by setting awk variables (colnum and require, in this case) and then using the literal string $colnum to get the desired field, and the variable require to get the required-string.

Note that in all cases (with or without the grep command), any regular expression meta-characters in $fileName will be meta-y, e.g., this.that will match the file named this.that but also the file named thisXthat.

Upvotes: 0

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