|
Size: 1297
Comment:
|
Size: 1058
Comment:
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 1: | Line 1: |
| = System Date = | = System Clock in Linux = |
| Line 3: | Line 3: |
| Linux distros often come with a wonky system date--both in the past (i.e., when the image was generated) and in a different timezone (usually GMT). This can cause significant issues on web servers, as signed SSL certificates are only valid within a date range. | The '''system clock''' in Linux generally uses the '''Coordinated Universal Time ''' ('''UTC''') standard, as opposed to '''localtime'''. |
| Line 5: | Line 5: |
| Set the timezone before trying to set the date. | Linux images often come with a wonky clock setting based on when the image was generated. This can cause significant issues on web servers, as signed SSL certificates are only valid within a date range. <<TableOfContents>> |
| Line 13: | Line 16: |
| The easy-to-use tool for setting timezones is `timedatectl`. | Use '''`timedatectl(1)`''' to set the local timezone. |
| Line 16: | Line 19: |
| timedatectl status # observe current setting timedatectl list-timezones # observe available settings timedatectl set-timezone Zone/SubZone # apply a new setting |
timedatectl status timedatectl list-timezones timedatectl set-timezone ZONE/SUBZONE |
| Line 21: | Line 24: |
| This is just a wrapper around `ln` however. The manual process is: | `timedatectl(1)` is a simple utility script; the manual equivalents roughly are... |
| Line 24: | Line 27: |
| realpath /etc/localtime # observe current setting ls /usr/share/zoneinfo # observe available zones ls /usr/share/zoneinfo/Zone # observe available subzones |
realpath /etc/localtime ls /usr/share/zoneinfo/* |
| Line 36: | Line 38: |
| The system date is set using the standard `date` utility, run as the superuser with an argument. | Use '''`date(1)`''' to set the current datetime. Note that `date(1)` must be called by the root user to set a datetime. |
| Line 39: | Line 41: |
| sudo date 2001011230 # sets system date to January 1st, 2020 at 12:30 | # January 1st, 2020 at 12:30 sudo date 2001011230 |
System Clock in Linux
The system clock in Linux generally uses the Coordinated Universal Time (UTC) standard, as opposed to localtime.
Linux images often come with a wonky clock setting based on when the image was generated. This can cause significant issues on web servers, as signed SSL certificates are only valid within a date range.
Contents
Timezone
Use timedatectl(1) to set the local timezone.
timedatectl status timedatectl list-timezones timedatectl set-timezone ZONE/SUBZONE
timedatectl(1) is a simple utility script; the manual equivalents roughly are...
realpath /etc/localtime ls /usr/share/zoneinfo/* ln -sf /usr/share/zoneinfo/Zone/SubZone /etc/localtime # apply a new setting
Date
Use date(1) to set the current datetime. Note that date(1) must be called by the root user to set a datetime.
# January 1st, 2020 at 12:30 sudo date 2001011230