我有以下命令:
diff -u filea fileb | grep '^-' | sed 's/^-//' > diff.txt
它工作得很好;它将每行的差异列表输出到文本文件中,然后删除每行的"-"的每个实例,但是我真的很想了解-u在做什么以及以下内容的含义:
Output NUM (default 2) lines of unified context
我是否正确地认为统一是指仅显示差异而不是差异的背景?
另外,对于使用上述命令将两个文件之间的差异显示到另一个文件的要求,我应该关注任何潜在的陷阱吗?
这
代表它找到的每个差异周围的"上下文行"的数量。
可能最好用一个例子来证明:
$ diff -U 1 hello.txt hello2.txt
--- hello.txt 2015-01-24 16:10:45.000000000 +0100
+++ hello2.txt 2015-01-24 16:11:14.000000000 +0100
@@ -4,3 +4,3 @@
Hello World.
-Hello World.
+Yo World.
Hello World.
$ diff -U 2 hello.txt hello2.txt
--- hello.txt 2015-01-24 16:10:45.000000000 +0100
+++ hello2.txt 2015-01-24 16:11:14.000000000 +0100
@@ -3,5 +3,5 @@
Hello World.
Hello World.
-Hello World.
+Yo World.
Hello World.
Hello World.
$ diff -U 3 hello.txt hello2.txt
--- hello.txt 2015-01-24 16:10:45.000000000 +0100
+++ hello2.txt 2015-01-24 16:11:14.000000000 +0100
@@ -2,7 +2,7 @@
Hello World.
Hello World.
Hello World.
-Hello World.
+Yo World.
Hello World.
Hello World.
Hello World.