Question

I have a text file with the following structure:

text1;text2;text3;text4
...

I need to write a script that gets 2 arguments: the column we want to search in and the content we want to find.

So the script should output only the lines (WHOLE LINES!) that match content(arg2) found in column x(arg1).

I tried with egrep and sed, but I’m not experienced enough to finish it. I would appreciate some guidance…

Answer 1

Given your added information of needing to output the entire line, awk is easiest:

awk -F';' -v col=$col -v pat="$val" '$col ~ pat' $input

Explaining the above, the -v options set awk variables without needing to worry about quoting issues in the body of the awk script. Pre-POSIX versions of awk won’t understand the -v option, but will recognize the variable assignment without it. The -F option sets the field separator. In the body, we are using a pattern with the default action (which is print); the pattern uses the variables we set with -v for both the column ($ there is awk‘s “field index” operator, not a shell variable) and the pattern (and pat can indeed hold an awk-style regex).