Sorting a Grep Command in Linux

When working with large amounts of data, sorting a grep command in Linux can be a crucial step in extracting relevant information. In this case, I typically choose not to sort so I can better see the hierarchical structure. However, if you really want sorted results, you can append `| sort -n` to your command.

A slightly different approach is to use `-x` to ensure that we stay on the same filesystem. This is particularly useful when working with limited disk space and you don't want to weed out files that are mounted within this FS tree or have been moved and symlinked back.

Here's a POSIX-compliant solution using `du` and `awk` that should work on every system:

`du -h | awk '{print $1, 'K' substr($2, index($2,'K')+1)}'`

This command does the following:

* Piping through a second `du` call to get the size of each file in human-readable format

* Using complicated shell/awk code to sort the results and discard extra columns

* Pulling out the numeric portion of the size

* Indexing the last character of the size field

* Printing the new fields - unit, value (to make the alpha-sort work properly it's zero-padded, fixed-length) and original line

The `BEGIN` block creates a string to index to substitute 1, 2, 3 for K, M, G for grouping by units, if there's no unit (the size is less than 1K), then there's no match and a zero is returned (perfect!).

This version uses `awk` to create extra columns for sort keys. I've split it into multiple lines, but it can be recombined into a one-liner.

By using this command, you can easily sort your grep results by size and extract the relevant information from large amounts of data.

Sort a grep command in linux