检查最后一个 diff 命令是否有输出

Question

我的文件中有一些类似的命令

diff file1 file2
diff file3 file4

如果有任何输出，我想打印发生在哪个命令中，例如

diff file1 file2
if (there was output from the diff command)
     print "file1 and file2 had the difference"
endif
diff file3 file4
if (there was output from the diff command)
     print "file3 and file4 had the difference"
endif

Answer 1

1如果存在差异，diff 命令将退出。最简单的方法是使用它作为成功/失败检查：

diff file1 file2 || print "file1 and file2 had the difference"
diff file3 file4 || print "file3 and file4 had the difference"