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🚀 Column introduction: This column mainly shares Linux technology, will involve the common Linux command operation, common service applications and related operation and maintenance knowledge, as well as some Linux system in-depth analysis.

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Telnet and SCP command usage between Linux servers

The Telnet command is used to test whether a port on a machine is accessible. Centos does not use this command by default. You need to install talent IP address +80To view80Port is clear (80Yum -y install xinetd Telnet Telnet -serverCopy the code
Telnet command:
Telnet IP address Port Application scenario: Test whether a port is accessibleCopy the code
SCP command: used to copy files or directories between servers
usage1SCP Directory where the local files are stored root@server IP address: directory where the local files are stored (root is also the user)Copy the code
Eg:192.16872.128./root/vmwareTools - for this machine10.2. 0-7259539.Copy the tar.gz file to192.16872.129.SCP /root/vmwaretools - (enter yes instead of y when prompted)10.2. 0-7259539.tar.gz root@192.16872.129.:/root/
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Usage 2: Copy files from another machine to a local directory. SCP root@server IP address: Server destination directory Specifies the directory where files are stored on the local server
Eg:192.16872.129./root/vmwareTools - for this machine10.2. 0-7259539.Copy the tar.gz file to192.16872.128.Under /root/, the following command is in128SCP root@ running on the machine192.16872.129.:/root/VMwareTools-10.2. 0-7259539.tar.gz /root/
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R parameter: recursive function (can copy directories)
Eg:128Scp-r vmware-tools-distrib root@ of the following operation192.16872.129.:/root/
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Linux process management command ps -ef and ps aux details

Introduction: This section describes the functions of the ps command

The ps command is used to display information about all processes. Ps and grep are used together to search for a specific process

[root@localhost ~]# ps -ef | more
root  2   0   0 Jul30  ?   00:00:00 [kthreadd]
root  3   2   0 Jul30  ?   00:00:06 [ksoftirqd/0]
root  5   2   0 Jul30  ?   00:00:00 [kworker/0:0H]
root  7   2   0 Jul30  ?   00:00:04 [migration/0]
root  8   2   0 Jul30  ?   00:00:00 [rcu_bh]
root  9   2   0 Jul30  ?   00:00:00 [rcuob/0]
root  10  2   0 Jul30  ?   00:00:00 [rcuob/1] UID: user ID PID: process ID PPID: parent process ID C: CPU usage STIME: process startup TIME TTY: TTY terminal TIME: total CPU usage since the process execution CMD: command to start the processCopy the code
[root@localhost ~]# ps aux | more
root 2 0.0 0.0 0 0 ? S Jul30 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? S Jul30 0:06 [ksoftirqd/0]
root 5 0.0 0.0 0 0 ? S< Jul30 0:00 [kworker/0:0H]
root 7 0.0 0.0 0 0 ? S Jul30 0:04 [migration/0]
root 8 0.0 0.0 0 0 ? S Jul30 0:00 [rcu_bh]
root 9 0.0 0.0 0 0 ? S Jul30 0:00 [rcuob/0]
root 10 0.0 0.0 0 0 ? S Jul30 0:00 [rcuob/1]
root 11 0.0 0.0 0 0 ? S Jul30 0:00 [rcuob/2] USER: which USER started the command PID: ID of a process %CPU: CPU usage %MEM: memory usage VSZ: total memory usage if a program resides in memory RSS: Current memory usage of a process TTY: TTY terminal STAT: Represents the state of the current process (S# In a dormant state; D# uninterruptible state; Z# zombie process; X# dead process)START: indicates the TIME when the COMMAND is started. TIME: indicates the total CPU usage since the process is executed. COMMAND: indicates the COMMAND used to START the processCopy the code

The ps -ef or ps aux command is usually executed to check whether our process has been started successfully, or to find the process number.

To forcibly stop the kill process, you can kill the PID of the main process directly

-9: #-9 is the number of kill signals displayed by kill -l. There are 64 kill signals. The number following kill -9 20846 is the PID of the process