You want to copy /etc/passwd to your home directory on 3 o'clock every Monday. What's the line that you should put in the crontab file?
时间: 2023-12-03 21:44:17 浏览: 41
The line that should be put in the crontab file to copy /etc/passwd to the home directory at 3 o'clock every Monday is:
```
0 3 * * 1 cp /etc/passwd /home/your_username/
```
This line specifies the following:
- `0 3 * * 1`: This means the command will run at 3:00 AM on any day of the month, any month, but only on Monday (`1` is the number assigned to Monday in cron).
- `cp /etc/passwd /home/your_username/`: This is the command that will be executed, which will copy the `/etc/passwd` file to your home directory.
相关问题
2.You want to copy /etc/passwd to your home directory on 3 o'clock every Monday. What's the line that you should put in the crontab file?
The line that should be added to the crontab file to copy /etc/passwd to the home directory on every Monday at 3 o'clock is:
```
0 3 * * 1 cp /etc/passwd /home/user/
```
Explanation:
- The first field `0` specifies the minutes when the command will run (i.e. 0 minutes).
- The second field `3` specifies the hour when the command will run (i.e. 3 AM).
- The third field `*` specifies the day of the month when the command will run (i.e. any day of the month).
- The fourth field `*` specifies the month when the command will run (i.e. any month).
- The fifth field `1` specifies the day of the week when the command will run (i.e. Monday).
- Finally, the command `cp /etc/passwd /home/user/` is the command that will be executed at the specified time.
Tell me about the meaning of each item in /etc/passwd
The /etc/passwd file is a system file on Unix-based operating systems that contains information about the user accounts on the system. Each line in the file represents a single user account and is in the following format:
username:password:UID:GID:GECOS:home_directory:shell
Here's a breakdown of what each item means:
- username: The name of the user account.
- password: An "x" or encrypted password for the user account. Modern systems store the actual encrypted password in a separate file called /etc/shadow.
- UID: The user ID number, a unique identifier assigned to the user account by the system.
- GID: The group ID number, which identifies the primary group for the user account.
- GECOS: General Electric Comprehensive Operating System field, also known as the "comment field." This field can contain additional information about the user, such as their full name, phone number, or other contact information.
- home_directory: The path to the user's home directory.
- shell: The default shell for the user account, which is the command interpreter that's used when the user logs in.