[wplug] Line-by-line input from stdin, from a bash script?

[Vance Kochenderfer]

Pat Barron <pat at lectroid.com> wrote:
> On 10/15/2013 12:51 PM, Eric Cooper wrote:
> > line=$(head -1)
> 
> I didn't even know that's something you can do...  ;-)

Just as a general shell scripting note, $(command) does the same
thing as `command`.  The backquotes are the traditional syntax,
while the other is newer but should be supported most everywhere
(it's been in the POSIX standard since 1997, if not earlier).

The $( ) form is a bit more robust.  I try to use it exclusively
in any new scripts.  There are special rules about how backslashes
and quotes are treated within the backquotes form.
<http://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xcu_chap02.html#tag_23_02_06_03>
<http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_03>

Somewhat related, there is a bashism, $(< file), which is the same
as $(cat file).  It is slightly faster since it doesn't fire up an
instance of cat, but it is NOT part of POSIX.

Vance Kochenderfer        |  "Get me out of these ropes and into a
vkochend at nyx.net          |   good belt of Scotch"    -Nick Danger