Re: [PLUG] Awk *language*: was Win Subsystem for Linux2 broken

[Walt Mankowski via plug <plug@lists.phillylinux.org>]

On Thu, Sep 10, 2020 at 12:10:33PM -0400, Rich Freeman via plug wrote:
> On Thu, Sep 10, 2020 at 12:01 PM Walt Mankowski via plug
> <plug@lists.phillylinux.org> wrote:
> >
> > I used to still use awk for splitting files since the syntax was a bit
> > simpler than Perl, but cut(1) does the simple cases even more simply,
> > and for anything else I use `perl -a`.
> 
> Main thing I do with awk is use it to pull one field out of a record.
> 
> Stuff like:
> zfs list -t snapshot -r offline1/storage | awk '{ print $1}' | tail -n
> +2 | xargs -n 1 zfs destroy
> 
> This pulls up a list of snapshots, grabs just the first field of each,
> strips the headers, then deletes each one.
> 
> Is there an easier way to pull one field (not necessarily the first)
> out of a list?

For simple things I use cut(1). To pull out the first field you use

cut -f1

cut defaults to splitting on tabs. If you wanted to split on, say,
commas, you'd say

cut -d, -f2

to pull the second field from a CSV file. I just ran that command in a
pipeline this morning!

Unfortunately cut doesn't have a way to split on regular expressions,
so it doesn't work when there are a variable number of spaces between
fields. For your example I'd probably use perl instead:

perl -aE 'say $F[0]'

Or maybe it's $F[1]; I don't remember if $1 is the first or second
field in awk.

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