简单查找操作

一、which找可执行程序

1.命令字的检索

给定一个命令字，Linux从哪里去找对应的指令？

−别名：alias可查看

−内部命令：help可查看

−程序目录：记录在环境变量PATH 中

[root@hadoop ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/soft/hadoop/bin:/usr/soft/hadoop/sbin:/usr/soft/hbase/bin:/usr/soft/hive/bin:/usr/soft/jdk/bin:/usr/soft/phoenix/bin:/usr/soft/scala/bin:/usr/soft/spark/bin:/usr/soft/spark/sbin:/usr/soft/sqoop/bin:/root/bin

2.查找外部程序

which 工具

−用法：which [-a] 命令字.. ..

−从别名及程序目录中查找，但不从内部命令查找

[root@hadoop ~]# which ls cd
alias ls='ls --color=auto'
	/bin/ls
/usr/bin/which: no cd in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/soft/hadoop/bin:/usr/soft/hadoop/sbin:/usr/soft/hbase/bin:/usr/soft/hive/bin:/usr/soft/jdk/bin:/usr/soft/phoenix/bin:/usr/soft/scala/bin:/usr/soft/spark/bin:/usr/soft/spark/sbin:/usr/soft/sqoop/bin:/root/bin)
[root@hadoop ~]# which -a reboot
/sbin/reboot

3.命令字的冲突处理

 4.练习

检查命令字ls、mkdir、ifconfig的程序文件在哪里

[root@hadoop ~]# which ls mkdir ifconfig
alias ls='ls --color=auto'
	/bin/ls
/bin/mkdir
/sbin/ifconfig

尝试检查命令字cd、help 的可执行文件，解释执行结果

cd、help是内部命令

[root@hadoop ~]# which cd
/usr/bin/which: no cd in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/soft/hadoop/bin:/usr/soft/hadoop/sbin:/usr/soft/hbase/bin:/usr/soft/hive/bin:/usr/soft/jdk/bin:/usr/soft/phoenix/bin:/usr/soft/scala/bin:/usr/soft/spark/bin:/usr/soft/spark/sbin:/usr/soft/sqoop/bin:/root/bin)
[root@hadoop ~]# which help
/usr/bin/which: no help in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/soft/hadoop/bin:/usr/soft/hadoop/sbin:/usr/soft/hbase/bin:/usr/soft/hive/bin:/usr/soft/jdk/bin:/usr/soft/phoenix/bin:/usr/soft/scala/bin:/usr/soft/spark/bin:/usr/soft/spark/sbin:/usr/soft/sqoop/bin:/root/bin)

将命令uname复制为/root/un ，如何才能执行un 程序

 

二、locate找文档

1.建立文档索引库

updatedb工具

−记录当时Linux中所有文档的路径

−删除/增加文档以后，需要重新updatedb，才能反映到索引库

−默认位置：/var/lib/mlocate/mlocate.db

2.根据索引库查找文档

locate 检索工具

−用法1（文档路径包含）：locate 关键词

−用法2（文件名包含）：locate -b 关键词

−用法3（文件名=关键词）：locate -b '\关键词'

3.locate应用示例

任务目标

−找出存放位置或名称中包含passwd关键词的所有文档

−选项-c 可获取匹配结果数

[root@hadoop ~]# locate passwd    #命令没有安装
-bash: locate: command not found

安装locate命令，最后出现complete才成功

[root@hadoop ~]# yum install mlocate
base                                                                                             | 3.7 kB     00:00     
extras                                                                                           | 3.4 kB     00:00     
updates                                                                                          | 3.4 kB     00:00     
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package mlocate.x86_64 0:0.22.2-6.el6 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
========================================================================================================================
 Package                     Arch                       Version                          Repository                Size
========================================================================================================================
Installing:
 mlocate                     x86_64                     0.22.2-6.el6                     base                      86 k
 
Transaction Summary
========================================================================================================================
Install       1 Package(s)
 
Total download size: 86 k
Installed size: 279 k
Is this ok [y/N]: y
Downloading Packages:
mlocate-0.22.2-6.el6.x86_64.rpm                                                                  |  86 kB     00:00     
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : mlocate-0.22.2-6.el6.x86_64                                                                          1/1 
  Verifying  : mlocate-0.22.2-6.el6.x86_64                                                                          1/1 
 
Installed:
  mlocate.x86_64 0:0.22.2-6.el6                                                                                         
 
Complete!

更新数据库

[root@hadoop ~]# updatedb

[root@hadoop ~]# locate passwd #模糊匹配
/etc/passwd
/etc/passwd-
/etc/pam.d/passwd

[root@hadoop ~]# locate -b '\passwd'
/etc/passwd
/etc/pam.d/passwd
/usr/bin/passwd
[root@hadoop ~]# locate -c passwd;locate -bc '\passwd'
116
3

4.练习

为当前主机系统建立locate索引库

[root@hadoop ~]# updatedb

列出系统中名称为passwd或者以hosts开头的所有文件

[root@hadoop ~]# locate -b '\passwd'
/etc/passwd
/etc/pam.d/passwd
/usr/bin/passwd
[root@hadoop ~]# locate -b '\hosts'
/etc/hosts

新建文件/opt/new.txt，更新索引库再使用locate查找此文件

[root@hadoop ~]# touch /opt/new.txt
[root@hadoop ~]# updatedb
[root@hadoop ~]# locate -b '\new.txt'
/opt/new.txt