1.cat命令详解
cat 是concatnate(拼接)的简写.
语法：
cat file1 file2 file3 ....
作用：将文件内容拼接在一起进行输出
具体应用：
1).压缩空白行
加上-s参数压缩连续的空白行
amosli@amosli-pc:~/learn$ cat mutil_blank.txt
this
is
blank!
amosli@amosli-pc:~/learn$ cat -s mutil_blank.txt ＃压缩连续的空白行
this
is
blank!
移除所有的空白行,
tr -s "\n"
amosli@amosli-pc:~/learn$ cat mutil_blank.txt | tr -s "\n"
this
is
blank!
2).将制表符显示为^|
-T 参数
amosli@amosli-pc:~/learn$ cat file.py
def function():
var = 5;
next = 6;
third = 7;
amosli@amosli-pc:~/learn$ cat -T file.py # 加上参数-T，即可将制表符标示出来!
def function():
^Ivar = 5;
^I^Inext = 6;
^Ithird = 7;
3).显示行号
-n参数
amosli@amosli-pc:~/learn$ cat -n file.py ＃加上参数-n即可显示行号
1 def function():
2 var = 5;
3 next = 6;
4 third = 7;
5
2.录制与回放终端会话
amosli@amosli-pc:~/learn$ script -t 2> timing.log -a output.session#开始录制
Script started, file is output.session
amosli@amosli-pc:~/learn$ hello1
No command 'hello1' found, did you mean:
Command 'hello' from package 'hello-debhelper' (main)
Command 'hello' from package 'hello' (main)
hello1: command not found
amosli@amosli-pc:~/learn$ who
amosli tty7 2013-12-19 22:58
amosli pts/1 2013-12-19 22:59 (:0.0)
amosli pts/2 2013-12-19 23:16 (:0.0)
amosli@amosli-pc:~/learn$ time
real 0m0.000s
user 0m0.000s
sys 0m0.000s
amosli@amosli-pc:~/learn$ date
2013年 12月 20日 星期五 01:06:41 CST
amosli@amosli-pc:~/learn$ exit
exit #结束录制
Script done, file is output.session
播放录制：
amosli@amosli-pc:~/learn$ scriptreplay timing.log output.session #按播放命令序列输出
amosli@amosli-pc:~/learn$ hello1
No command 'hello1' found, did you mean:
Command 'hello' from package 'hello-debhelper' (main)
Command 'hello' from package 'hello' (main)
hello1: command not found
amosli@amosli-pc:~/learn$ who
amosli tty7 2013-12-19 22:58
amosli pts/1 2013-12-19 22:59 (:0.0)
amosli pts/2 2013-12-19 23:16 (:0.0)
amosli@amosli-pc:~/learn$ time
real 0m0.000s
user 0m0.000s
sys 0m0.000s
amosli@amosli-pc:~/learn$ date
2013年 12月 20日 星期五 01:06:41 CST
amosli@amosli-pc:~/learn$ exit
amosli@amosli-pc:~/learn$
进行多个用户之间进行广播视频会话：打开两个终端
(1)在终端１中输入以下命令：
mkfifo scriptfifo
(2)在终端２中输入以下命令:
cat scriptfifo
(3)返回终端１，输入以下命令：
script -f scriptfifo
commands...
这样就实现了广播，在线课堂类的作用，非常神奇！！
我自己实验的输出：
终端１：
amosli@amosli-pc:~$ mkfifo scriptfifo
amosli@amosli-pc:~$ script -f scriptfifo
Script started, file is scriptfifo
amosli@amosli-pc:~$ who
amosli tty7 2013-12-19 22:58
amosli pts/1 2013-12-19 22:59 (:0.0)
amosli pts/2 2013-12-20 01:14 (:0.0)
amosli pts/4 2013-12-20 01:16 (:0.0)
amosli pts/5 2013-12-20 01:20 (:0.0)
amosli pts/6 2013-12-20 01:20 (:0.0)
amosli@amosli-pc:~$
终端２：
amosli@amosli-pc:~$ cat scriptfifo
Script started on 2013年12月20日 星期五 01时21分19秒
amosli@amosli-pc:~$ who
amosli tty7 2013-12-19 22:58
amosli pts/1 2013-12-19 22:59 (:0.0)
amosli pts/2 2013-12-20 01:14 (:0.0)
amosli pts/4 2013-12-20 01:16 (:0.0)
amosli pts/5 2013-12-20 01:20 (:0.0)
amosli pts/6 2013-12-20 01:20 (:0.0)
amosli@amosli-pc:~$