Linux commands: History

Life Introduction to the Order:

The role of the Linux History command is to record commands that have been executed. Usage: History [n] n is a number, listing the most recent n command-C removes all history commands from the current shell to the history [-raw] Histfiles-a writes the currently new command to Histfiles, which is written by default ~/.bash_hi Story-r reads Histfiles content into the current shell's history memory-W writes the current history memory to Histfiles

1. command format:

History [n] n is a number

2. Command function:

1. View the command history

2. Clear the command history

3. Save Command history

3. Command parameters:

-C : Empty command history

- D [n]: Delete a command at the specified location

- W : Save the Command history to the history file

4. usage Examples:

Example one: view the last 10 command history

[[Email protected] default]# history 10
1218 passwd Tom
1219 File Useradd
1220 cd/etc/default/
1221 LL
1222 file Useradd
1223 Cat Useradd
1224 Q
1225 Man
1226 Mans 1 History
1227 History 10

Instance one: use! Execute history command.

1,! Number executes the first few commands

2,! Command executes from the most recent command, with commands beginning with

3,!! Perform the previous article

[Email protected] default]#!1222
File Useradd
Useradd:ascii text

[Email protected] default]#!fil
File Useradd
Useradd:ascii text

< Span style= "Font-family:simsun;" >

[[email protected " default]# < Span style= "Font-family:simsun;" >

File Useradd
Useradd:ascii text

Example Two : History configuration changes

EG1, History record line number

[Email protected] tmp]# echo $HISTSIZE
1000

EG2, default record 1000 line configuration file modified in/etc/profile

[Email protected] tmp]# cat/etc/profile-n

histsize=1000

eg3, historical command files are recorded in ~/.bash_history
To get the history command of Linux to display time, history is defaulted without time, added in/etc/profile

Export histtimeformat= "%y-%m-%d%h:%m:%s"

EG4, view. bash_history

Head ~/.bash_history

example Three:Same account number of simultaneous logins written to history

When you log on to the system with bash, the system reads the previously run commands from ~/.bash_history.

When you log off, update the latest Histsize command to the ~/.bash_history file.

When the same account is logged in to more than one bash at the same time, only the last Exit is written to Bash_history, and the others are overwritten.

History-w is forced to write immediately, keeping only the latest.

example Four:Ctrl+r Reverse Query History command

Use the Ctrl+r reverse query History command to display the latest matching match if you want to continue to query upward, press Ctrl+r

[[Email protected] ~]# History 6
1238 Cat. Bash_history
1239 Rpm-q Bind-lib

(reverse-i-search) 'rpm': rpm-q bind-lib <<== ctrl+r after input rpm

Linux commands: History