57 lines
2.0 KiB
Markdown
57 lines
2.0 KiB
Markdown
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# The `reboot` Command
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The `reboot` command is used to restart a linux system. However, it requires elevated permission using the [sudo](https://github.com/bobbyiliev/101-linux-commands-ebook/blob/main/ebook/en/content/051-the-sudo-command.md) command. Necessity to use this command usually arises after significant system or network updates have been made to the system.
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## Syntax
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```
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reboot [OPTIONS...]
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```
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### Options
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- **–help** : This option prints a short help text and exit.
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- **-halt** : This command will stop the machine.
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- **-w**, **–wtmp-only** : This option only writes wtmp shutdown entry, it do not actually halt, power-off, reboot.
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### Examples
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1. Basic Usage. Mainly used to restart without any further details
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```
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$ sudo reboot
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```
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However, alternatively the shutdown command with the `-r` option
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```
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$ sudo shutdown -r now
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```
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**Note** that the usage of the reboot, halt and power off is almost similar in syntax and effect. Run each of these commands with –help to see the details.
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2. The `reboot` command has limited usage, and the `shutdown` command is being used instead of reboot command to fulfill much more advance reboot and shutdown requirements. One of those situations is a scheduled restart. Syntax is as follows
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```
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$ sudo shutdown –r [TIME] [MESSAGE]
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```
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Here the TIME has various formats. The simplest one is `now`, already been listed in the previous section, and tells the system to restart immediately. Other valid formats we have are +m, where m is the number of minutes we need to wait until restart and HH:MM which specifies the TIME in a 24hr clock.
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**Example to reboot the system in 2 minutes**
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```
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$ sudo shutdown –r +2
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```
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**Example of a scheduled restart at 03:00 A.M**
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```
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$ sudo shutdown –r 03:00
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```
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3. Cancelling a Reboot. Usually happens in case one wants to cancel a scheduled restart
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**Syntax**
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```
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$ sudo shutdown –c [MESSAGE]
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```
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**Usage**
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```
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$sudo shutdown -c "Scheduled reboot cancelled because the chicken crossed the road"
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```
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4. Checking your reboot logs
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```
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$ last reboot
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```
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