Linux命令cat运用讲解lianxi

1、linux命令cat运用讲解linux 命令 cat - concatenate files and print on the standard output 把文件连接后输出到屏幕 上，其实就是查看文件内容。你们知道什么是linux命令么这个非常高深的运用技术将由我來非常讲解，linux命令 nb在哪呢，下面我来进入讲述linux命令的无限领域。linux 命令 cat - concatenate files and print on the standard output 把文件连接后输出到屏幕 上，其实就是查看文件内容。synopsiscat option filedescription

2、concatenate file(s), or standard input, to standard output.-a,show-allequivalent to -vet -等同与参数-vetbnumber-nonblanknumber nonblank output lines 一对空白行不编号，与有相似。-e,equivalent to -ve 一等同与参数ve-e,show-ends display $ at end of each line -每行以$符号为行结尾-n,number number all output lines 由1开始对所有输岀的行数编号-s,squeeze-

3、blank never more than one single blank line -当遇到连续 2 行以上的空白彳亍，只 保留一行空白行t,equivalent to -vt-t,show-tabsdisplay tab characters as ai-uxignored)-v,show-nonprintinguse a and m- notation, except for lfd and tablinux命令练习：frootcentos4 ok_0081# cat mytesthello world!hello world 1hello world 2hello world 3ro

4、otcentos4 ok_008j# cat -n mytesthello world!hello world 1hello world 2hello world 3lrootcentos4 ok_008j# cat -b mytest1 hello world!2hello world 13hello world 24hello world 3从以上linux命令 我们可以验证与b的差异。rootcentos4 ok_008# cat -b -e mytest1 hello world !$2hello world 1$3hello world 2$4hello world 3$每行以$符号

5、为行结尾现在想合并mytest和okicst两个文件的内容成一个新的文件newtest.txtrootcentos4 ok_008# is -ltotal 24-rw-r-r- 1 root root 59 sep 18 19:48 mytestdrwxr-xr-x 3 root root 4096 sep 13 22:51 ok-rw-rr 1 root root 21 sep 17 20:45 oktestrootcentos4 ok_008# cat mytest oktest » newtest.txtrootcentos4 ok_008j# is -ltotal 32-rw

6、-r-r- 1 root root 59 sep 18 19:48 mytest-rw-r-r- 1 root root 80 sep 18 19:53 newtest.txtdrwxr-xr-x 3 root root 4096 sep 13 22:51 ok-rw-rr 1 root root 21 sep 17 20:45 oktest 查看新的文件 newtest.txt 的内容:frootcentos4 ok_008# cat -b newtest.txt1 hello world!2 hello world 13 hello world 24 hello world 35 this

7、 is a test file.合并两个文件的内容jootcentos4 ok_008j# cat mytest oktest > newtest 1 .txtrootcentos4 ok_008# is -ltotal 401 root root 59 sep 18 19:48 mytest-rw-r-r- 1 root root 80 sep 18 19:56 newtestl.txtrw-rr 1 root root 80 sep 18 19:53 newtest.txtdrwxr-xr-x 3 root root 4096 sep 13 22:51 okrw-r-r- 1 roo

8、t root 21 sep 17 20:45 oktestrootcentos4 ok_008# cat -b newtestl.txt1 hello world!2 hello world 13 hello world 24 hello world 35 this is a test file.我们仔细会发现 cat mytest oktest > newtest 1 .txt 和 cat mytest oktest » newtest.txt 返冋 的结果在这里相同。其实根据linux常用命令 全集的例子：cat -n textfile 1 > textfile2把

9、textfile 1的档案内容加上行号后输入textfile2这个档案里cat -b textfile 1 textfile2 » textfile3把textfile 1和textfile2的档案内容加上行号（空白行不加）z后将内容附可以看出 两个linux命令 的差异，这里就不多写例子。linux命令清空某个文件的内容：rootcentos4 ok_008# cat /dev/null > mytestrootcentos4 ok_008# cat -b mytestfrootcentos4 ok_008# is -1total 52-rw-rr 1 root root 0

10、 sep 18 20:05 mytest-rw-rr 1 root root 80 sep 18 19:56 newtestl.txt-rw-r-r- 1 root root 93 sep 18 20:01 newtest3.txt-rw-rr- 1 root root 93 sep 18 20:01 newtest4.txt-rw-rr 1 root root 80 sep 18 19:53 newtest.txtdrwxr-xr-x 3 root root 4096 sep 13 22:51 ok-rw-rr- 1 root root 34 sep 18 20:00 oktestlinux

11、命令创建一个新的文件：frootcentos4 ok_008# cat >new.txt 一按 ctrl + c 结束录入rootcentos4 ok_008# is -1total 561 root root 0 sep 18 20:05 mytest-rw-r-r- 1 root root 80 sep 18 19:56 newtestl.txt-rw-r-r- 1 root root 93 sep 18 20:01 newtest3.txt-rw-r-r 1 root root 93 sep 18 20:01 newtest4.txt1 root root 80 sep 18 19

12、:53 newtest.txt-rw-rr 1 root root 0 sep 18 20:07 new.txtdrwxr-xr-x 3 root root 4096 sep 13 22:51 ok-rw-rr 1 root root 34 sep 18 20:00 oktestlinux命令温习以前的rmlinux命令 把一些刚才临吋建立的文件(如 newtest 1 .txt,newtest3.txt,newtest4.txt,newtest.txt.new.txt)®*除掉：frootcentos4 ok_0081# rm newtestl.txt newttest3.txt

13、newtest4.txt newtest.txtrm: remove regular file "newtestl.txt1? yrm: cannot lstatvnewttest3.txt1: no such file or directoryrm: remove regular file、newtest4.txt1? yrm: remove regular fileewtest.txt1? y frootcentos4 ok_008# rm newtest3.txt rm: remove regular file vnewtest3.txt*? y rootcentos4 ok_

14、008# is -1 total 24-rw-r-r- 1 root root 0 sep 18 20:05 mytest-rw-rr 1 root root 0 sep 18 20:07 new.txt drwxr-xr-x 3 root root 4096 sep 13 22:51 ok -rw-r-r- 1 root root 34 sep 18 20:00 oktest rootcentos4 ok_008# rm newt.txt rm: cannot lstat "newt.txt1: no such file or directory rootcentos4 ok_0()8# rm new.txt rm