A small remark: 'diff A B' works OK, but 'diff -u A B' does not. Adding --color does not change anything.
"diff -ud A B" brings only *one* 'program error' plus a "+Abort" message (Exit 134): tiger pete 225 /\ /opt/local/var/macports/build/_Users_btest_ports_sysutils_diffutils/diffutils/work/diffutils-3.12/src/diff --color --minimal -u Portfile-graphite2-312 Portfile-graphite2 --- Portfile-graphite2-312 2025-06-17 08:43:05.000000000 +0200 +++ Portfile-graphite2 2025-06-17 08:42:18.000000000 +0200 @@ -31,10 +22,19 @@ compiler.cxx_standard \ 2011 -set py_ver 3.12 -set py_ver_nodot [string map {. {}} ${py_ver}] - -test.run yes diff: program error +Abort Exit 134 The last two lines are green. "diff: program error" and "compiler.cxx_standard \\ 2011" are in terminal text colour. Leaving '--minimal' away produces: tiger pete 226 /\ /opt/local/var/macports/build/_Users_btest_ports_sysutils_diffutils/diffutils/work/diffutils-3.12/src/diff --color -u Portfile-graphite2-312 Portfile-graphite2 --- Portfile-graphite2-312 2025-06-17 08:43:05.000000000 +0200 +++ Portfile-graphite2 2025-06-17 08:42:18.000000000 +0200 @@ -27,14 +18,23 @@ diff: program error diff: program error Abort Exit 134 Anyway, I am going backwards! -- Greetings Pete <\ \__ O __O | O\ _\\/\-% _`\<, '()-'-(_)--(_) (_)/(_)