sed编辑器不会修改原始文件。你删除的行只是从sed编辑器的输出中消失了。原始文件仍然包含那些“删掉的”行
macname@localhost Desktop % cat data1
1The quick brown fox jumps over the lazy dog
2The quick brown fox jumps over the lazy dog
3The quick brown fox jumps over the lazy dog
4The quick brown fox jumps over the lazy dog
5The quick brown fox jumps over the lazy dog
6The quick brown fox jumps over the lazy dog
7The quick brown fox jumps over the lazy dog
macname@localhost Desktop %
删除第二行
macname@localhost Desktop % sed '2d' data1 1The quick brown fox jumps over the lazy dog 3The quick brown fox jumps over the lazy dog 4The quick brown fox jumps over the lazy dog 5The quick brown fox jumps over the lazy dog 6The quick brown fox jumps over the lazy dog 7The quick brown fox jumps over the lazy dog
删除第二行和第三行
macname@localhost Desktop % sed '2,3d' data1 1The quick brown fox jumps over the lazy dog 4The quick brown fox jumps over the lazy dog 5The quick brown fox jumps over the lazy dog 6The quick brown fox jumps over the lazy dog 7The quick brown fox jumps over the lazy dog
删除第二行和第三行
macname@localhost Desktop % macname@localhost Desktop % cat ddd 一The quick brown fox jumps over the lazy dog 二The quick brown fox jumps over the lazy dog 三The quick brown fox jumps over the lazy dog 四The quick brown fox jumps over the lazy dog 五The quick brown fox jumps over the lazy dog 六The quick brown fox jumps over the lazy dog 七The quick brown fox jumps over the lazy dog macname@localhost Desktop % macname@localhost Desktop % sed '2,3d' ddd 一The quick brown fox jumps over the lazy dog 四The quick brown fox jumps over the lazy dog 五The quick brown fox jumps over the lazy dog 六The quick brown fox jumps over the lazy dog 七The quick brown fox jumps over the lazy dog
删除第三行，以及之后的所有行
macname@localhost Desktop % sed '3,$d' data1 1The quick brown fox jumps over the lazy dog 2The quick brown fox jumps over the lazy dog
删除第二行和第五行，以及这两行之间的所有行
macname@localhost Desktop % sed '/2/,/5/d' data1 1The quick brown fox jumps over the lazy dog 6The quick brown fox jumps over the lazy dog 7The quick brown fox jumps over the lazy dog macname@localhost Desktop %
这里是通过内容匹配的
macname@localhost Desktop % cat ddd 一The quick brown fox jumps over the lazy dog 二The quick brown fox jumps over the lazy dog 三The quick brown fox jumps over the lazy dog 四The quick brown fox jumps over the lazy dog 五The quick brown fox jumps over the lazy dog 六The quick brown fox jumps over the lazy dog 七The quick brown fox jumps over the lazy dog macname@localhost Desktop % macname@localhost Desktop % sed '/2/,/5/d' ddd 一The quick brown fox jumps over the lazy dog 二The quick brown fox jumps over the lazy dog 三The quick brown fox jumps over the lazy dog 四The quick brown fox jumps over the lazy dog 五The quick brown fox jumps over the lazy dog 六The quick brown fox jumps over the lazy dog 七The quick brown fox jumps over the lazy dog macname@localhost Desktop % sed '/二/,/五/d' ddd 一The quick brown fox jumps over the lazy dog 六The quick brown fox jumps over the lazy dog 七The quick brown fox jumps over the lazy dog macname@localhost Desktop %
除此之外，你要特别小心，因为只要sed编辑器在数据流中匹配到了开始模式，删除功能就 会打开。这可能会导致意外的结果。
第二个出现数字“1”的行再次触发了删除命令，因为没有找到停止模式，所以就将数据流中的剩余行全部删除了。
macname@localhost Desktop % cat data1 1The quick brown fox jumps over the lazy dog 2The quick brown fox jumps over the lazy dog 3The quick brown fox jumps over the lazy dog The quick brown fox jumps over the lazy 1 dog 4The quick brown fox jumps over the lazy dog 5The quick brown fox jumps over the lazy dog 6The quick brown fox jumps over the lazy dog 7The quick brown fox jumps over the lazy dog macname@localhost Desktop % macname@localhost Desktop % sed '/1/,/3/d' data1 macname@localhost Desktop % macname@localhost Desktop %
当然，如果你指定了一个从未在文本中出现的停止模式，显然会出现另外一个问题。
因为删除功能在匹配到第一个模式的时候打开了，但一直没匹配到结束模式，所以整个数据 流都被删掉了。
macname@localhost Desktop % macname@localhost Desktop % sed '/1/,/10/d' data1 macname@localhost Desktop %