Malformed ExternalProject grep command in AIX nightly build

I noticed the output below in the test log for the ExternalProject test case on one of the nightly build AIX machines. I can’t see where the malformed grep command could be coming from. @chuckatkins @ben.boeckel would either of you be able to take a look at the files involved on that machine?

[ 20%] Creating directories for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
[ 20%] Performing download step (git clone) for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
-- Avoiding repeated git clone, stamp file is up to date: '/home/atkins3/Dashboards/CMake/Builds/GCC_7.2.0/CMake-build/Tests/ExternalProject/CMakeExternals/Stamp/TS1-GIT-RECURSIVE_SUBMODULES-off/TS1-GIT-RECURSIVE_SUBMODULES-off-gitclone-lastrun.txt'
[ 20%] Performing update step for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
grep: illegal option -- a
usage: grep [-r] [-R] [-H] [-L] [-E|-F] [-c|-l|-q] [-insvxbhwyu] [-p[parasep]] -e pattern_list...
	[-f pattern_file...] [file...]
usage: grep [-E|-F] [-c|-l|-q] [-insvxbhwyu] [-p[parasep]] [-e pattern_list...]
	-f pattern_file... [file...]
usage: grep [-E|-F] [-c|-l|-q] [-insvxbhwyu] [-p[parasep]] pattern_list [file...]
Current branch master is up to date.
[ 20%] No patch step for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
[ 20%] Performing configure step for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
-- Configuring done
-- Generating done
-- Build files have been written to: /home/atkins3/Dashboards/CMake/Builds/GCC_7.2.0/CMake-build/Tests/ExternalProject/CMakeExternals/Build/TS1-GIT-RECURSIVE_SUBMODULES-off
[ 22%] No build step for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
[ 25%] No install step for 'TS1-GIT-RECURSIVE_SUBMODULES-off'
[ 25%] Completed 'TS1-GIT-RECURSIVE_SUBMODULES-off'
[ 25%] Built target TS1-GIT-RECURSIVE_SUBMODULES-off

Strangely, it doesn’t seem to be causing the update command to fail, which seems like a bug too. That’s a separate issue, but if you happen to work out why that is while looking for the malformed grep command, that would also be helpful.

That particular machine is currently having network filesystem problems that are causing these failures. I’ve moved the builds to the “Temporarily Problematic Nightly” section of our dashboard for now. As for the grep, I’m guessing it is coming from external tooling that is perhaps confused by NFS timeouts.