9 Feb
2020
9 Feb
'20
5:35 a.m.
On Sat, Feb 8, 2020, 4:29 PM Rob Pike <robpike(a)gmail.com> wrote:
% rc
% whatis cd
builtin cd
%
It's much simpler this way. The output is the executable input, free of
decoration and ready to use.
In today's Unix (I use the term loosely) world, the phrase "free of
decoration" is apostasy.
A number of utilities have a special flag to use in shell scripts to remove
the decorations. I both like and loath this design pattern.
Warner
-rob
On Sun, Feb 9, 2020 at 10:26 AM Chet Ramey <chet.ramey(a)case.edu> wrote:
On 2/8/20 6:11 PM, Rob Pike wrote:
Not for me it doesn't.
% bash
bash-3.2$ function f() {
echo hi
}
bash-3.2$ export f
bash-3.2$ bash
bash-3.2$ f
bash-3.2$
jenna(1)$ echo $BASH_VERSION
5.0.11(6)-release
jenna(1)$ f() { echo f; }
jenna(1)$ export -f f
jenna(1)$ bash
jenna(2)$ f
f
jenna(2)$
It works the same in Mac OS X's bash-3.2.
I added the 'builtin' command, which
did leave the labs. But I added it
as
a way for the "whatis" command to show
a builtin, as well as allowing a
way
to guarantee you get the builtin on execution.
Bash uses `type' to tell whether something is a builtin. How does
`builtin'
say whether or not a command is builtin? The output with no arguments?
How do I get bash to print the function as
(shell) source code, so I
could
edit it and play with it again? It was the
synergy of all this stuff
connected seamlessly that made it so compelling.
jenna(2)$ declare -pf f
f ()
{
echo f
}
declare -fx f
If it weren't exported, you wouldn't get the `declare' command appended
there.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU chet(a)case.edu http://tiswww.cwru.edu/~chet/