linux指令-cat-tac

cat-tac

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 2021/02/19   Share

linux指令-cat-tac

cat指令以及tac指令用来查看文件的内容，使用也是十分便利

命令格式：

# cat
cat [OPTION]... [FILE]...

# tac
tac [OPTION]... [FILE]...

参数：

cat参数	解释
-b	列出行号，只列出非空白行，空白行不进行编号
-n	列出行号，空白行也进行编号
-E	将结尾的断行字符$打印出来
-T	将tab以^I打印出来
-v	列出一些看不出来的特殊字符
-A	相当于-vET的整合，列出特殊字符

演示：

查看/etc/man_db.conf

[root@VM-8-14-centos ~]# cat /etc/man_db.conf
#
#
# This file is used by the man-db package to configure the man and cat paths.
# It is also used to provide a manpath for those without one by examining
# their PATH environment variable. For details see the manpath(5) man page.
# 以下部分省略

显示行号（-n与-b的区别）

[root@VM-8-14-centos ~]# cat -b /etc/issue
     1  \S
     2  Kernel \r on an \m

[root@VM-8-14-centos ~]# cat -n /etc/issue
     1  \S
     2  Kernel \r on an \m
     3

列出所有特殊字符

[root@VM-8-14-centos ~]# cat -A /etc/man_db.conf
# $
#$
# This file is used by the man-db package to configure the man and cat paths.$
# It is also used to provide a manpath for those without one by examining$
# their PATH environment variable. For details see the manpath(5) man page.$
#$
# Lines beginning with `#' are comments and are ignored. Any combination of$
# tabs or spaces may be used as `whitespace' separators.$
#$
# There are three mappings allowed in this file:$
# 以下部分省略

在windows和linux中，断行符号是不一样的，在linux中，断行符号为$，而在windows中，断行符号为^M$。我们在windows中写一个txt文件，然后发送到linux中查看，看一下断行符的样子

1
2
3

[root@VM-8-14-centos ~]# cat -A windows.txt
aaaaaaaaaaaaaaaaaaaaaa^M$
bbbbbbbbbbbbbbbbbb^M$

行数较少的文件，使用cat查看即可，一旦文件的行数较多，使用cat查看是不便利的，应当使用less、more等命令查看

至于tac命令，就是将文件以相反的顺序输出，就犹如cat与tac字母位置的区别

[root@VM-8-14-centos ~]# cat /etc/issue
\S
Kernel \r on an \m

[root@VM-8-14-centos ~]# tac /etc/issue

Kernel \r on an \m
\S

原文作者：sui

原文链接：http://example.com/2021/02/19/linux%E6%8C%87%E4%BB%A4-cat-tac/

发表日期：February 19th 2021, 10:44:26 am

更新日期：February 19th 2021, 10:44:52 am

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