Operate on the body of a file but not the header

Sometimes you need to run some UNIX command on a file but only want to operate on the body of the file, not the header. Create a file called body somewhere in your $PATH, make it executable, and add this to it:

#!/bin/bash
IFS= read -r header
printf '%s\n' "$header"
eval $@

Now, when you need to run something but ignore the header, use the body command first. For example, we can create a simple data set with a header row and some numbers:

$ echo -e "header\n1\n5\n4\n7\n3"
header
1
5
4
7
3

We can pipe the whole thing to sort:

$ echo -e "header\n1\n5\n4\n7\n3" | sort
1
3
4
5
7
header

Oops, we don’t want the header to be included in the sort. Let’s use the body command to operate only on the body, skipping the header:

$ echo -e "header\n1\n5\n4\n7\n3" | body sort
header
1
3
4
5
7

Sure, there are other ways to solve the problem with sort, but body will solve many more problems. If you have multiple header rows, just call body multiple times.

Inspired by this post on Stack Exchange.

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