Having trouble with simple awk script - bash

Question

This works in the command line:
awk -F, '$5>1900 {print $2}' presidents.csv
But I am not sure how to do it in an awk script.
This is what I have tried so far in the script.
BEGIN {FS=","}
if ($5>1900)
{print $2}

Answer 1

The stuff you have in single quotes:
awk -F, '$5>1900 {print $2}' presidents.csv
Is an AWK script. Just stick that in a file:
BEGIN {FS=","}
$5>1900 {print $2}

Answer 2

AWK requires a pattern to search for and an action to be taken when it finds the pattern. Either pattern or action can be omitted but not both.
In your case first its a syntax mistake as you haven't enclosed your action within braces ( {} ) and so this will cause AWK to think both pattern and action got omitted. We can use relational expression as pattern in AWK and so instead of using an if statement you can use the relational expression as below.
$ cat test.awk
#!/usr/bin/awk -f
BEGIN {
FS=",";
}
$5 >= 1900 {
print $2;
}

Answer 3

AWk script would be like,
#!/usr/bin/awk
BEGIN {FS=",";}
{
if ($5>1900)
{print $2;}
}
That is, you need to enclose the if condition inside curly braces.

Answer 4

If you'd like a shell script that runs your awk command you can put the following into a file:
#!/bin/bash
awk -F, '$1>1900 {print $2}' $1
To make it so you can actually execute the script, you can run:
chmod +x ./script_file_name_here
Then you can run
./script_file_name_here presidents.csv
and have the same thing happen.