Re: "sed" question

On 2024-03-06, Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:

$ awk '{print $1, "1-1"}'  newsrc-news.eternal-september.org-test >
newsrc-news.eternal-september.org

>
In this specific case of regular data you can simplify that to
>
  awk '$2="1-1"'  sourcefile > targetfile

That had me scratching my head.  You can't have an action without
enclosing braces.  But it's still legal syntax because... it's an
expression serving as a pattern.  The assignment itself is a side
effect.
Care needs to be taken when using this shortcut so the expression
doesn't evalute as false:
$ printf 'one 1\ntwo 2\nthree 3\n' | awk '$2=4'          one 4
two 4
three 4
$ printf 'one 1\ntwo 2\nthree 3\n' | awk '$2=0' $ $ printf 'one 1\ntwo 2\nthree 3\n' | awk '$2="4"'
one 4
two 4
three 4
$ printf 'one 1\ntwo 2\nthree 3\n' | awk '$2=""'
$ --
Christian "naddy" Weisgerber                          naddy@mips.inka.de