How to Execute Cron Jobs Every Second in Linux
銆€銆€Many times, our scheduled tasks need to run with second-level precision, but Linux only supports scheduling down to the minute by default. Most built-in versions of Linux don’t natively support second-level execution. Using sleep makes it easy to execute tasks by the second.
1. The sleep format is as follows:
sleep 5 …
SSH fails to start on Linux, and attempting to start sshd on the server results in an error. The message reads: /var/empty/sshd must be owned by root and not group or world-writable.
Following the prompt, it’s likely a permissions issue, so check the sshd status and permissions:
# /etc/init.d/ …
1. Count the number of files in the current folder: ls -l |grep "^-"|wc -l
2. Count the number of directories in the current folder: ls -l |grep "^d"|wc -l 3. Count the number of files in the current folder, including those in subfolders: ls -lR|g …
When editing a document as a regular user in Linux, you may encounter the “W10: Warning: Changing a readonly file” prompt. Here’s how to fix it:
Normally, press i to edit, then press ESC, and then press Shift+Z+Z to save. If you get the error above, press ESC after editing, then …
I. Installing Chinese Support on the System
1. Install Chinese language pack:
yum -y groupinstall chinese-support
2. Modify character encoding configuration file
vi /etc/sysconfig/i18n
Enter:
LANGUAGE=”zh_CN.GB18030:zh_CN.GB2312:zh_CN”
SUPPORTED=”zh_CN.GB18030:zh_C …
Today, while editing a file I encountered the error: E45: Warning: Changing a readonly file, E45: ‘readonly’ option is set. The message essentially indicates insufficient permissions. Even after re-running chown with root, the prompt persisted. After some trial and error, here is the solution for your reference …
Sometimes, to quickly install a piece of software, we have to use the yum method, but it can be frustrating when the yum package isn’t found. Below, we’ll install EPEL to add a yum repository and fix this:
Using CentOS as an example, here is the installation method:
CentOS 6 32-bit: rpm -ivh http://dl. …
Today while performing a system directory file backup, I encountered a problem: a .sh script file could be executed manually, but when added to a scheduled task, it would exit after compressing the backup file to a certain size.
After searching online, I finally found the answer. The solution is as follows:
The script file in my original crontab was like …
crontab is a commonly used scheduled task tool in the system. Below we will explain its usage:
1. Edit directly with the crontab command
The cron service provides the crontab command to configure the cron service. Here are some parameters and explanations for this command:
crontab -u //Set up cron service for a specific user, …
The command format is:
date -s time-string
For example, to only modify the system date without changing the time (hours, minutes, seconds)
date -s 2016-03-16
Or to only modify the time without changing the date
date -s 10:08:00
Of course, you can also modify both date and time simultaneously
date -s "2016-03-16 04:53:00" …
