-bash-4.1# ll /etc/rc.local lrwxrwxrwx. 1 root root 13 Aug 15 2014 /etc/rc.local -> rc.d/rc.local
-bash-4.1# cat /etc/rc.local #!/bin/sh touch /var/lock/subsys/local route add default gw 192.169.1.1 service iptables stop echo "hosfore test line"
</pre><pre code_snippet_id="684937" snippet_file_name="blog_20150605_4_1032646" name="code" class="cpp" style="color: rgb(68, 68, 68);">-bash-4.1# sed -i "/hosfore/s//jane/" /etc/rc.local -bash-4.1# cat /etc/rc.local #!/bin/sh touch /var/lock/subsys/local route add default gw 192.169.1.1 service iptables stop echo "jane test line"
</pre><pre code_snippet_id="684937" snippet_file_name="blog_20150605_6_4535175" name="code" class="cpp"><span style="color:#ff0000;">-bash-4.1# ll /etc/rc.local -rwxr-xr-x 1 root root 300 Jun 5 09:47 /etc/rc.local -bash-4.1# cat /etc/rc.d/rc.local #!/bin/sh touch /var/lock/subsys/local route add default gw 192.169.1.1 service iptables stop echo "hosfore test line"</span>
</pre><pre code_snippet_id="684937" snippet_file_name="blog_20150605_8_4167031" name="code" class="cpp">-bash-4.1# rm /etc/rc.local -bash-4.1# ln -s /etc/rc.d/rc.local /etc/rc.local -bash-4.1# ll /etc/rc.local lrwxrwxrwx 1 root root 18 Jun 5 09:51 /etc/rc.local -> /etc/rc.d/rc.local -bash-4.1# cat /etc/rc.local #!/bin/sh touch /var/lock/subsys/local route add default gw 192.169.1.1 service iptables stop echo "hosfore test line"
-bash-4.1# sed -i <strong>--follow-symlinks</strong> "/hosfore/s//jane/" /etc/rc.local -bash-4.1# ll /etc/rc.local lrwxrwxrwx 1 root root 18 Jun 5 09:51 /etc/rc.local -> /etc/rc.d/rc.local -bash-4.1# cat /etc/rc.d/rc.local #!/bin/sh touch /var/lock/subsys/local route add default gw 192.169.1.1 service iptables stop echo "jane test line"
如上所看到的，使用“sed -i "/hosfore/s//jane/" /etc/rc.local ”命令改动文件之后，发现这个文件变成普通文件了 ，查询sed的使用手冊，可知，假设须要保持软硬链接属性，改动的时候须要加上相应參数：
man sed
DESCRIPTION
Sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipeline). While in some ways similar to an editor which permits scripted edits (such as ed), sed works by making only one pass over the input(s), and is consequently more efficient. But it is sed's ability to filter text in a pipeline which particularly distinguishes it from other types of editors.
--follow-symlinks
follow symlinks when processing in place; hard links will still be broken.
-i [SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if extension supplied). The default operation mode is to break symbolic and hard links. This can be changed with --follow-symlinks and --copy.
-c, --copy
use copy instead of rename when shuffling files in -i mode. While this will avoid breaking links (symbolic or hard), the resulting editing operation is not atomic. This is rarely the desired mode; --follow-symlinks is usually enough, and it is both faster and more secure.