a historical command
1. Grammar
history [options] [history command save file]
Options:
-c: clear history command
-w: Write the history commands in the cache to the history command save file ~/.bash_histoty
1000 historical commands are saved by default, and can be modified in the environment variable configuration file /etc/profile.
2. History command calling method
3. Command and file completion
In Bash, command and file completion are very convenient and commonly used functions. As long as we press the "Tab" key when entering a command or file, it will be automatically completed.
Two actual combat
[root@localhost ~]# history -w
[root@localhost ~]# history
1 cat .bash_history
2 history -w
3 history
[root@localhost ~]# vi /etc/profile
[root@localhost ~]# history
1 cat .bash_history
2 history -w
3 history
4 vi /etc/profile
5 history
[root@localhost ~]# !3
history
1 cat .bash_history
2 history -w
3 history
4 vi /etc/profile
5 history
6 history
[root@localhost ~]# !!
history
1 cat .bash_history
2 history -w
3 history
4 vi /etc/profile
5 history
6 history
[root@localhost ~]# !cat
cat .bash_history
cat .bash_history
history -w
[root@localhost ~]# user
useradd userdel userhelper usermod usernetctl users
[root@localhost ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@localhost ~]# cd /
bin/ dev/ home/ lib/ media/ mydata/ proc/ run/ srv/ tmp/ var/
boot/ etc/ japan/ lib64/ mnt/ opt/ root/ sbin/ sys/ usr/
[root@localhost ~]# cd /
bin/ dev/ home/ lib/ media/ mydata/ proc/ run/ srv/ tmp/ var/
boot/ etc/ japan/ lib64/ mnt/ opt/ root/ sbin/ sys/ usr/
[root@localhost ~]# cd /usr/
bin/ etc/ games/ include/ lib/ lib64/ libexec/ local/ sbin/ share/ src/ tmp/
[root@localhost ~]# cd /usr/l
lib/ lib64/ libexec/ local/
[root@localhost ~]# cd /usr/l
lib/ lib64/ libexec/ local/
[root@localhost ~]# cd /usr/local/