Concerning the unified output format, POSIX says in http://pubs.opengroup.org/onlinepubs/9699919799/utilities/diff.html
"If -U n is specified, the output shall contain no more than n consecutive unaffected lines; and if the output contains an affected line and this line is adjacent to up to n consecutive unaffected lines in the corresponding file, the output shall contain these unaffected lines. -u shall act like -U3." but with GNU diff and n = 3, one can get up to 6 consecutive unaffected lines: @@ -1,14 +1,14 @@ 1 2 3 -4 +4b 5 6 7 8 9 10 -11 +11b 12 13 14 I actually think that the GNU diff behavior is better than POSIX. And it is quite strange that POSIX specifies something different because this format comes from GNU diff! I think that the GNU diff manual should say something about this difference. Or could this be regarded as a defect in POSIX? Note: I noticed this after seeing that Subversion's internal diff behaves again differently, with a behavior between GNU diff and POSIX: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=777479#17 -- Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
