Danh Doan <congdanhqx@xxxxxxxxx> writes: > A comment in test-lib-functions::test_cmp mentions that > there _is_ a diff out there that doesn't understand "-u". That came from 82ebb0b6 (add test_cmp function for test scripts, 2008-03-12). The change history at the end of the page: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/diff.html suggests that POSIX did not require "diff -u" until Issue 7, so it is not surprising that the lack of "diff -u" to cause test_cmp to fail was of real concern back in March 2008, as the application of the errata have been only an year and half old, according to: https://www.opengroup.org/austin/docs/austin_325.txt I vaguely recall that some open source projects only took the copied context diffs and not unified ones the last time I checked, but admittedly (1) that "last time" was a long time ago and (2) our popularity and the fact that we do not understand copied context [*1*] may have forced people to move away from "-c" and adopt "-u" at the same time. So it might be OK to write off any system that does not understand "diff -u" as an unusable trash these days ;-) IOW, I think I am fine with assuming "diff -u" is available, like Dscho's patch does. Thanks. [Footnote] *1* It used to be my desire to teach "git apply" and "git diff" to also work with copied context format, but procrastination made it less and less relevant X-<.
