The same thing stands for GNU coreutils (`brew install coreutils`); here's macOS `cut` vs GNU `cut` as a quick example.
~ $ cut --help
cut: illegal option -- -
usage: cut -b list [-n] [file ...]
cut -c list [file ...]
cut -f list [-s] [-d delim] [file ...]
~ $ gcut --help
Usage: gcut OPTION... [FILE]...
Print selected parts of lines from each FILE to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --bytes=LIST select only these bytes
-c, --characters=LIST select only these characters
-d, --delimiter=DELIM use DELIM instead of TAB for field delimiter
-f, --fields=LIST select only these fields...
-n (ignored)
--complement complement the set of selected bytes, characters or fields
-s, --only-delimited do not print lines not containing delimiters
--output-delimiter=STRING use STRING as the output delimiter
the default is to use the input delimiter
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exitBut yes, sometimes POSIX or the C standard or whatever is too restrictive, but it's still a good starting point for figuring out how to write portable code.
You'll know anything it doesn't cover is implementation-specific, and then either decide it's not worth it to pursue it, or if it is figure out whether the implementations you're targeting support the feature.
I have twenty years of experience in getting that page to show up in search results. :)
Currently, a good way to get to it is these search terms:
posix issue 7
Haha! I love that you acknowledge this because usually people just ignore all the experience they have in getting to the right page and make it look like you're dumb for not being able to find it. Thanks for the pointer! :-)
http://pubs.opengroup.org/onlinepubs/7908799/
Ha, that didn't use frames yet! Totally forgot about that.
You might find this [2] helpful (oops, seems like it got deleted, see [3] - thanks @bionoid)
[1] https://www.gnu.org/software/gawk/manual/gawk.html
[2] https://www.reddit.com/r/awk/comments/4omosp/differences_bet...
https://www.removeddit.com/r/awk/comments/4omosp/differences...
Archive for posterity: http://archive.is/btGky
Sure, try this:
echo 1 2 | awk '{ print gensub(/1/, "3", "g", $1); }'
If I may rant about this for a bit, GNU software manuals are generally rather awful (though they're neither alone in this nor is it impossible to find exceptions). They frequently make absolutely zero effort to display important information more prominently and unimportant information less so (if you're even lucky enough that they tell you the important information in the first place). Like if passing --food will accidentally blow up a nuke in your hometown, you can expect that if they documented it at all, they just casually buried it in the middle of some random paragraph. Their operating assumption seems to be that if you can't be bothered to spend the next 4 hours reading a novel before writing your one-liner then it's just obviously your fault for sucking so much.
> Those functions that are specific to gawk are marked with a pound sign (‘#’). They are not available in compatibility mode (see section Command-Line Options)
To be fair though, every time I have read the manual for a gawk function it clearly says "this is a gawk extension" for non-standard implementations (case in point, delete[1], which is now POSIX, although Mac's awk is too old to have that implemented).
[1] https://www.gnu.org/software/gawk/manual/html_node/Delete.ht...