Linux command search commands whereis and which

a whereis

1. Grammar

whereis command name

The path where the search command is located and where the help documentation is located

Options:

-b: look for executable files only

-m: find only help files

2. Actual combat

1. [root@localhost ~]# whereis ls
2. ls:/usr/bin/ls /usr/share/man/man1/ls.1.gz/usr/share/man/man1p/ls.1p.gz
3. [root@localhost ~]# whoami
4. root
5. [root@localhost ~]# whatis
6. whatis what?
7. [root@localhost ~]# whatis ls
8. ls (1)- list directory contents
9. ls (1p)- list directory contents
10. [root@localhost ~]# whereis -b ls
11. ls:/usr/bin/ls
12. [root@localhost ~]# whereis -m ls
13. ls:/usr/share/man/man1/ls.1.gz/usr/share/man/man1p/ls.1p.gz

二 which

1. Grammar

which command name

Search command path and alias

2. Actual combat

1. [root@localhost ~]# which ls
2. alias ls='ls --color=auto'
3. /usr/bin/ls
4. [root@localhost ~]# which pwd
5. /usr/bin/pwd
6. [root@localhost ~]# whereis cd
7. cd:/usr/bin/cd /usr/share/man/man1/cd.1.gz/usr/share/man/man1p/cd.1p.gz
8. [root@localhost ~]# which cd
9. /usr/bin/cd

Three PATH environment variables

Defines the path of the system search command

1. [root@localhost ~]# echo $PATH
2. /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin