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:~$
