Report versions of gm, ffmpeg, etc.

[PaulWessel]

Finally figured out how to deal with programs such as gm and ffmpeg who decided it is a good idea not to have a --version option, so we instead are forced to grep and awk and cut etc to get the obvious answers.

[seisman]

What if we don't have bash on Windows?

[PaulWessel]

OK, shall I put it inside
if (WIN32)
and only do the version if not Windows?

[seisman]

In the top CMakLists, we have the FindUnixCommands directive, which can find if bash, gzip, tar et al. are available (see https://cmake.org/cmake/help/latest/module/FindUnixCommands.html).

gmt/CMakeLists.txt

Line 74 in da90090

include (FindUnixCommands)

I believe we can check if ${BASH} is defined.

[seisman]

The Windows CI has bash, and returns:

*  Found GhostScript (gs)     : yes
*  Found GraphicsMagick (gm)  : no
*  Found ffmpeg               : no
*  Found open                 : yes
*  Found ogr2ogr              : yes (2.4.1)
*  Found gdal_translate       : yes (2.4.1)

[PaulWessel]

So no gm and ffmpeg installed? The test checks if they exist before we try to get versions. And seems to work for the GDAL tools.

[seisman]

gm and ffmpeg are only installed when we run the whole tests.

[PaulWessel]

OK, so it works on Windows if bash is installed. is it likely that there will be people running cmake on Windows and not have bash? 99.9% of Windows users will install from the binary installer, no? Is it worth adding an if-test? Perhaps cmake will stop if one of these fails due to lack of bash, so safest to add that protection?

[seisman]

This is what I get on Windows. I have git bash installed, but I don't add it to my PATH, so it's invisible to cmake.

OK, so it works on Windows if bash is installed.

Strictly speaking, no. Having bash installed doesn't mean tr and cut are also available. But I think it's OK to me. If someone doesn't have bash, tr or cut, then the versions are empty.

[PaulWessel]

Can we do better than the awkward tr ',' ' ' | cut -f2 -d' and head -n 1 | cut -f2 -d' ' ?

[seisman]

OK for me. Hopefully it also works for @joa-quim.

[PaulWessel]

Let's wait to accept this PR until @joa-quim has tried it.

[seisman]

Can we do better than the awkward tr ',' ' ' | cut -f2 -d' and head -n 1 | cut -f2 -d' ' ?

I believe I found a better way. Will try if it works.

[PaulWessel]

I guess it is a question of ${AWK} is more likely to be available in Windows than tr and head. We could do

gm help | awk '{if (NR == 1) print $2}'
ogr2ogr --version | awk -F, '{print $1}'

for instance.

[seisman]

Closed as #1853 is better.