On Thu, 26 Nov 2020 20:58:38 GMT, Magnus Ihse Bursie <i...@openjdk.org> wrote:
> For historical reasons, there exists a variety of different implementations > of awk: awk (the original implementation), gawk (the GNU version), nawk (new > awk, iirc) and the lesser known mawk. > > Things are complicated by the fact that the original awk is seldom used, but > instead gawk or nawk is typically symlinked to be named "awk". > > In terms of functionality there are very few differences. The original awk is > most limited, while nawk and gawk is mostly replaceable. > > So the conditions for this is somewhat messy, but we manage impressively to > mess it up even further. :-) > > We set up the following definitions: > `BASIC_REQUIRE_PROGS(NAWK, [nawk gawk awk])` > `BASIC_REQUIRE_SPECIAL(AWK, [AC_PROG_AWK])` > and `AC_PROG_AWK`, according to the documentation, "[c]heck for gawk, mawk, > nawk, and awk, in that order". > > So, if you have nawk and awk (but no other) installed, both NAWK and AWK will > be set to nawk. If you have only awk, both will be set to awk. The difference > is if you have gawk installed, then NAWK will be nawk and AWK will be gawk. > > As an example, on my mac, I only have the original awk, so both AWK and NAWK > will be awk. > > On my ubuntu box, things are even more confused. I have: > $ ls -l /usr/bin/*awk > lrwxrwxrwx 1 root root 21 Feb 6 10:36 awk -> /etc/alternatives/awk* > -rwxr-xr-x 1 root root 658072 Feb 11 2018 gawk* > -rwxr-xr-x 1 root root 3189 Feb 11 2018 igawk* > -rwxr-xr-x 1 root root 125416 Apr 3 2018 mawk* > lrwxrwxrwx 1 root root 22 Feb 6 10:37 nawk -> /etc/alternatives/nawk* > > $ ls -l /etc/alternatives/*awk > lrwxrwxrwx 1 root root 13 Feb 10 10:56 /etc/alternatives/awk -> > /usr/bin/gawk* > lrwxrwxrwx 1 root root 13 Feb 10 10:56 /etc/alternatives/nawk -> > /usr/bin/gawk* > > So awk, nawk and gawk all executes the same binary, i.e. gawk. Only mawk is > different. So on that machine, AWK would be gawk and NAWK would be nawk, but > both will execute gawk. > > I propose that we remove NAWK, and only use AWK, but we should stop using > AC_PROG_AWK and define it in an order that is transparent to us. I recommend > [gawk nawk awk], since on Linux systems nawk (as we've seen) is likely to be > gawk under disguise anyway, so it's better to be clear about that. > > This reasoning assumes that the awk scripts we write are portable enough to > be executed by any awk. If we run into any problem with this, we might have > to restrict the variation of awks we support. > > To make this work properly, I also needed to get rid of the awk launched by > fixpath in CompileCommand. (This only worked. since AWK was not evolved to a > full path by `AC_PROG_AWK`, but was only `awk`(or whatever). Otherwise this > could not work with fixpath, so it was very much a hack to begin with... This pull request has now been integrated. Changeset: a3e1980c Author: Magnus Ihse Bursie <i...@openjdk.org> URL: https://git.openjdk.java.net/jdk/commit/a3e1980c Stats: 35 lines in 15 files changed: 4 ins; 9 del; 22 mod 8256541: Sort out what version of awk is used in the build system Reviewed-by: erikj ------------- PR: https://git.openjdk.java.net/jdk/pull/1470
