Learn Linux commands every day--history

　　The function of the history command is to display and number the used commands. The following commands are the different operations of the history:

History n shows the most recently used n commands.

History-c clears the history of the current shell.

history-d 801 Delete the command with number 801.

History-a append the latest command to the history file.

History-n shows a history that has not yet been read from the history file.

History-r the record in the history file as the history of the current shell.

History-w writes the current record to the history file, overwriting the original content.

The system default History command is difficult to meet our needs, we can modify the/etc/profile file to the hostory command

To modify the display effect:

(1) Show the time of the command execution

Add at the end of the/etc/profile file: Export histtimeformat= "%F%T ' WhoAmI ':" (note: Here WhoAmI both sides of the symbol is not a single quotation mark, but the TAB key above the symbol of the key, that is ~ the symbol below.) ）

(2) Displays the source IP of the user executing the command

First get login source ip:user_ip= ' who-u am I 2>/dev/

null | awk ' {print &nf} ' | Sed-e ' s/[()]//g "

If ["&user_ip" = ""]

Then

User_ip= ' hostname '

Then export Histtimeformat, user_ip as a parameter to write Histtimeformat,

Export histtimeformat= "%F%T &user_ip: ' WhoAmI ':"

Combining the above tips, we can get the following script:

user_ip= ' who-u am I 2>/dev/null | awk ' {print &nf} ' |sed-e ' s/[()]//g '

If ["&user_ip" = ""]

Then

User_ip= ' hostname '

Fi

if [!-d/opt/history]

Then

Mkdir/opt/history

chmod 777/opt/history

Fi

if [!-d/opt/history/&{logname}]

Then

Mkdir/opt/history/&{logname}

chmod 300/opt/history/&{logname}

Fi

Export histsize=4096

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

Export histfile= "/opt/history/${logname}.history"

chmod 600/opt/history/*history* 2>/dev/null

Append the above code to the end of the/etc/profile file and log in again, and you will find that the display format of the history and the storage file are changed.

Learn Linux commands every day--history