Re: env: add -S option (split string for shebang lines in scripts)

[Assaf Gordon]

Hello,

Attached updated patch, two main improvements:
1. preserves empty arguments, e.g.
       env -S echo "" bar
2. prints an error message on incorrect shebang usage:

     $ cat xxx
     #!src/env -v -S cat -n

     $ ./xxx
     src/env: possible incorrect usage of env in a script
     Try 'src/env --help' for more information.

Item 2 is implemented in a separate patch (number 9) to ease review.

Of course the error message could be improved, as can the detection
if the exact circumstances, but I'm not sure it's warranted.

On 01/05/18 04:48 PM, Bernhard Voelker wrote:
> On 05/01/2018 06:40 PM, Eric Blake wrote:
> > #!/usr/bin/env -S -P /usr/bin:/opt/bin:${PATH} perl

"env -Ppath" is not implemented in this patch, but if we think it's
worth while I'll add it in next patch.

> So regarding -S, I'm currently a bit worried about whether a +413 lines
> change to the 185 lines env.c source is really warranted ... but I have
> to admit that I don't see how -S could be supported in an easier way).

This is certainly a judgment call (whether this feature is bloat or
useful enough).

The amount of code is the same ball-park number as the BSD 
implementation (mine is slightly more verbose and with more comments):
https://github.com/freebsd/freebsd/blob/master/usr.bin/env/envopts.c

Binary-wise, these are the size differences with --debug and with -S:

$ size src/env.orig src/env.debug src/env.debug.s
   text    data     bss     dec     hex filename
  26521    1424     448   28393    6ee9 src/env.orig
  27313    1456     480   29249    7241 src/env.debug
  31027    1512     480   33019    80fb src/env.debug.s



regards,
 - assaf

env-S-2018-05-05.patch.gz
Description: application/gzip