diff --git a/sources/tech/20190926 How to Execute Commands on Remote Linux System over SSH.md b/sources/tech/20190926 How to Execute Commands on Remote Linux System over SSH.md new file mode 100644 index 0000000000..18d629c0b6 --- /dev/null +++ b/sources/tech/20190926 How to Execute Commands on Remote Linux System over SSH.md @@ -0,0 +1,423 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) +[#]: subject: (How to Execute Commands on Remote Linux System over SSH) +[#]: via: (https://www.2daygeek.com/execute-run-linux-commands-remote-system-over-ssh/) +[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/) + +How to Execute Commands on Remote Linux System over SSH +====== + +We may need to perform some commands on the remote machine. + +To do so, log in to a remote system and do it, if it’s once in a while. + +But every time you do this, it can irritate you + +If so, what is the better way to get out of it. + +Yes, you can do this from your local system instead of logging in to the remote system. + +Will it benefit me? Yeah definitely. This will save you good time. + +How’s that happening? Yes, SSH allows you to run a command on a remote machine without logging in to a computer. + +**The general syntax is as follow:** + +``` +$ ssh [User_Name]@[Rremote_Host_Name or IP] [Command or Script] +``` + +### 1) How to Run the Command on a Remote Linux System Over SSH + +The following example allows users to run the **[df command][1]** via ssh on a remote Linux machine + +``` +$ ssh [email protected] df -h + + Filesystem Size Used Avail Use% Mounted on + /dev/mapper/centos-root 27G 4.4G 23G 17% / + devtmpfs 903M 0 903M 0% /dev + tmpfs 920M 0 920M 0% /dev/shm + tmpfs 920M 9.3M 910M 2% /run + tmpfs 920M 0 920M 0% /sys/fs/cgroup + /dev/sda1 1014M 179M 836M 18% /boot + tmpfs 184M 8.0K 184M 1% /run/user/42 + tmpfs 184M 0 184M 0% /run/user/1000 +``` + +### 2) How to Run Multiple Commands on a Remote Linux System Over SSH + +The following example allows users to run multiple commands at once over ssh on the remote Linux system. + +It’s running uptime command and free command on the remote Linux system simultaneously. + +``` +$ ssh [email protected] "uptime && free -m" + + 23:05:10 up 10 min, 0 users, load average: 0.00, 0.03, 0.03 + + total used free shared buffers cached + Mem: 1878 432 1445 1 100 134 + -/+ buffers/cache: 197 1680 + Swap: 3071 0 3071 +``` + +### 3) How to Run the Command with sudo Privilege on a Remote Linux System Over SSH + +The following example allows users to run the **fdisk** command with **[sudo][2]** [][2]**[privilege][2]** on the remote Linux system via ssh. + +Normal users are not allowed to execute commands available under the system binary **(/usr/sbin/)** directory. Users need root privileges to run it. + +So to run the **[fdisk command][3]** on a Linux system, you need root privileges. + +The which command returns the full path of the executable of the given command. + +``` +$ which fdisk + /usr/sbin/fdisk +``` + +``` +$ ssh -t [email protected] "sudo fdisk -l" + [sudo] password for daygeek: + + Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors + Units = sectors of 1 * 512 = 512 bytes + Sector size (logical/physical): 512 bytes / 512 bytes + I/O size (minimum/optimal): 512 bytes / 512 bytes + Disk label type: dos + Disk identifier: 0x000bf685 + + Device Boot Start End Blocks Id System + /dev/sda1 * 2048 2099199 1048576 83 Linux + /dev/sda2 2099200 62914559 30407680 8e Linux LVM + + Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors + Units = sectors of 1 * 512 = 512 bytes + Sector size (logical/physical): 512 bytes / 512 bytes + I/O size (minimum/optimal): 512 bytes / 512 bytes + + Disk /dev/mapper/centos-root: 29.0 GB, 28982640640 bytes, 56606720 sectors + Units = sectors of 1 * 512 = 512 bytes + Sector size (logical/physical): 512 bytes / 512 bytes + I/O size (minimum/optimal): 512 bytes / 512 bytes + + Disk /dev/mapper/centos-swap: 2147 MB, 2147483648 bytes, 4194304 sectors + Units = sectors of 1 * 512 = 512 bytes + Sector size (logical/physical): 512 bytes / 512 bytes + I/O size (minimum/optimal): 512 bytes / 512 bytes + + Connection to centos7.2daygeek.com closed. +``` + +### 4) How to Run the Service Command with sudo Privilege on a Remote Linux System Over SSH + +The following example allows users to run the service command with sudo privilege on the remote Linux system via ssh. + +``` +$ ssh -t [email protected] "sudo systemctl restart httpd" + + [sudo] password for daygeek: + Connection to centos7.2daygeek.com closed. +``` + +### 5) How to Run the Command on a Remote Linux System Over SSH With Non-Standard Port + +The following example allows users to run the **[hostnamectl command][4]** via ssh on a remote Linux machine with non-standard port. + +``` +$ ssh -p 2200 [email protected] hostnamectl + + Static hostname: Ubuntu18.2daygeek.com + Icon name: computer-vm + Chassis: vm + Machine ID: 27f6c2febda84dc881f28fd145077187 + Boot ID: bbeccdf932be41ddb5deae9e5f15183d + Virtualization: oracle + Operating System: Ubuntu 18.04.2 LTS + Kernel: Linux 4.15.0-60-generic + Architecture: x86-64 +``` + +### 6) How to Save Output from Remote System to Local System + +The following example allows users to remotely execute the **[top command][5]** on a Linux system via ssh and save the output to the local system. + +``` +$ ssh [email protected] "top -bc | head -n 35" > /tmp/top-output.txt +``` + +``` +cat /tmp/top-output.txt + + top - 01:13:11 up 18 min, 1 user, load average: 0.01, 0.05, 0.10 + Tasks: 168 total, 1 running, 167 sleeping, 0 stopped, 0 zombie + %Cpu(s): 0.0 us, 6.2 sy, 0.0 ni, 93.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st + KiB Mem : 1882300 total, 1176324 free, 342392 used, 363584 buff/cache + KiB Swap: 2097148 total, 2097148 free, 0 used. 1348140 avail Mem + PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND + 4943 daygeek 20 0 162052 2248 1612 R 10.0 0.1 0:00.07 top -bc + 1 root 20 0 128276 6936 4204 S 0.0 0.4 0:03.08 /usr/lib/sy+ + 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [kthreadd] + 3 root 20 0 0 0 0 S 0.0 0.0 0:00.25 [ksoftirqd/+ + 4 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [kworker/0:+ + 5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kworker/0:+ + 7 root rt 0 0 0 0 S 0.0 0.0 0:00.00 [migration/+ + 8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [rcu_bh] + 9 root 20 0 0 0 0 S 0.0 0.0 0:00.77 [rcu_sched] + 10 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [lru-add-dr+ + 11 root rt 0 0 0 0 S 0.0 0.0 0:00.01 [watchdog/0] + 13 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [kdevtmpfs] + 14 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [netns] + 15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [khungtaskd] + 16 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [writeback] + 17 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kintegrity+ + 18 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [bioset] + 19 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [bioset] + 20 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [bioset] +``` + +Alternatively, you can use the following format to run multiple commands on a remote system. + +``` +$ ssh [email protected] << EOF +hostnamectl +free -m +grep daygeek /etc/passwd +EOF +``` + +Output of the above command. + +``` +Pseudo-terminal will not be allocated because stdin is not a terminal. + Static hostname: CentOS7.2daygeek.com + Icon name: computer-vm + Chassis: vm + Machine ID: 002f47b82af248f5be1d67b67e03514c + Boot ID: dca9a1ba06374d7d96678f9461752482 + Virtualization: kvm + Operating System: CentOS Linux 7 (Core) + CPE OS Name: cpe:/o:centos:centos:7 + Kernel: Linux 3.10.0-957.el7.x86_64 + Architecture: x86-64 + + total used free shared buff/cache available + Mem: 1838 335 1146 11 355 1314 + Swap: 2047 0 2047 + + daygeek:x:1000:1000:2daygeek:/home/daygeek:/bin/bash +``` + +### 7) How to Execute Local Bash Scripts on Remote System + +The following example allows users to run local **[bash script][6]** “remote-test.sh” via ssh on a remote Linux machine. + +Create a shell script and execute it. + +``` +$ vi /tmp/remote-test.sh + +#!/bin/bash +#Name: remote-test.sh +#-------------------- + uptime + free -m + df -h + uname -a + hostnamectl +``` + +Output for the above command. + +``` +$ ssh [email protected] 'bash -s' < /tmp/remote-test.sh + + 01:17:09 up 22 min, 1 user, load average: 0.00, 0.02, 0.08 + + total used free shared buff/cache available + Mem: 1838 333 1148 11 355 1316 + Swap: 2047 0 2047 + + Filesystem Size Used Avail Use% Mounted on + /dev/mapper/centos-root 27G 4.4G 23G 17% / + devtmpfs 903M 0 903M 0% /dev + tmpfs 920M 0 920M 0% /dev/shm + tmpfs 920M 9.3M 910M 2% /run + tmpfs 920M 0 920M 0% /sys/fs/cgroup + /dev/sda1 1014M 179M 836M 18% /boot + tmpfs 184M 12K 184M 1% /run/user/42 + tmpfs 184M 0 184M 0% /run/user/1000 + + Linux CentOS7.2daygeek.com 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux + + Static hostname: CentOS7.2daygeek.com + Icon name: computer-vm + Chassis: vm + Machine ID: 002f47b82af248f5be1d67b67e03514c + Boot ID: dca9a1ba06374d7d96678f9461752482 + Virtualization: kvm + Operating System: CentOS Linux 7 (Core) + CPE OS Name: cpe:/o:centos:centos:7 + Kernel: Linux 3.10.0-957.el7.x86_64 + Architecture: x86-64 +``` + +Alternatively, the pipe can be used. If you think the output is not good, add few changes to make it more elegant. + +``` +$ vi /tmp/remote-test-1.sh + +#!/bin/bash +#Name: remote-test.sh + echo "---------System Uptime--------------------------------------------" + uptime + echo -e "\n" + echo "---------Memory Usage---------------------------------------------" + free -m + echo -e "\n" + echo "---------Disk Usage-----------------------------------------------" + df -h + echo -e "\n" + echo "---------Kernel Version-------------------------------------------" + uname -a + echo -e "\n" + echo "---------HostName Info--------------------------------------------" + hostnamectl + echo "------------------------------------------------------------------" +``` + +Output for the above script. + +``` +$ cat /tmp/remote-test.sh | ssh [email protected] + Pseudo-terminal will not be allocated because stdin is not a terminal. + ---------System Uptime-------------------------------------------- + 03:14:09 up 2:19, 1 user, load average: 0.00, 0.01, 0.05 + + ---------Memory Usage--------------------------------------------- + total used free shared buff/cache available + Mem: 1838 376 1063 11 398 1253 + Swap: 2047 0 2047 + + ---------Disk Usage----------------------------------------------- + Filesystem Size Used Avail Use% Mounted on + /dev/mapper/centos-root 27G 4.4G 23G 17% / + devtmpfs 903M 0 903M 0% /dev + tmpfs 920M 0 920M 0% /dev/shm + tmpfs 920M 9.3M 910M 2% /run + tmpfs 920M 0 920M 0% /sys/fs/cgroup + /dev/sda1 1014M 179M 836M 18% /boot + tmpfs 184M 12K 184M 1% /run/user/42 + tmpfs 184M 0 184M 0% /run/user/1000 + tmpfs 184M 0 184M 0% /run/user/0 + + ---------Kernel Version------------------------------------------- + Linux CentOS7.2daygeek.com 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux + + ---------HostName Info-------------------------------------------- + Static hostname: CentOS7.2daygeek.com + Icon name: computer-vm + Chassis: vm + Machine ID: 002f47b82af248f5be1d67b67e03514c + Boot ID: dca9a1ba06374d7d96678f9461752482 + Virtualization: kvm + Operating System: CentOS Linux 7 (Core) + CPE OS Name: cpe:/o:centos:centos:7 + Kernel: Linux 3.10.0-957.el7.x86_64 + Architecture: x86-64 +``` + +### 8) How to Run Multiple Commands on Multiple Remote Systems Simultaneously + +The following bash script allows users to run multiple commands on multiple remote systems simultaneously. Use simple for loop to achieve it. + +For this purpose, you can try with with the **[PSSH command][7]** or **[ClusterShell command][8]** or **[DSH command][9]** + +``` +$ vi /tmp/multiple-host.sh + + for host in CentOS7.2daygeek.com CentOS6.2daygeek.com + do + ssh [email protected]${host} "uname -a;uptime;date;w" + done +``` + +Output for the above script: + +``` +$ sh multiple-host.sh + + Linux CentOS7.2daygeek.com 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux + + 01:33:57 up 39 min, 1 user, load average: 0.07, 0.06, 0.06 + + Wed Sep 25 01:33:57 CDT 2019 + + 01:33:57 up 39 min, 1 user, load average: 0.07, 0.06, 0.06 + USER TTY FROM [email protected] IDLE JCPU PCPU WHAT + daygeek pts/0 192.168.1.6 01:08 23:25 0.06s 0.06s -bash + + Linux CentOS6.2daygeek.com 2.6.32-754.el6.x86_64 #1 SMP Tue Jun 19 21:26:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux + + 23:33:58 up 39 min, 0 users, load average: 0.00, 0.00, 0.00 + + Tue Sep 24 23:33:58 MST 2019 + + 23:33:58 up 39 min, 0 users, load average: 0.00, 0.00, 0.00 + USER TTY FROM [email protected] IDLE JCPU PCPU WHAT +``` + +### 9) How to Add a Password Using the sshpass Command + +If you are having trouble entering your password each time, I advise you to go with any one of the methods below as per your requirement. + +If you are going to perform this type of activity frequently, I advise you to set up **[password-less authentication][10]** since it’s a standard and permanent solution. + +If you only do these tasks a few times a month. I recommend you to use the **“sshpass”** utility. + +Just provide a password as an argument using the **“-p”** option. + +``` +$ sshpass -p 'Your_Password_Here' ssh -p 2200 [email protected] ip a + + 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 + link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 + inet 127.0.0.1/8 scope host lo + valid_lft forever preferred_lft forever + inet6 ::1/128 scope host + valid_lft forever preferred_lft forever + 2: eth0: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 + link/ether 08:00:27:18:90:7f brd ff:ff:ff:ff:ff:ff + inet 192.168.1.12/24 brd 192.168.1.255 scope global dynamic eth0 + valid_lft 86145sec preferred_lft 86145sec + inet6 fe80::a00:27ff:fe18:907f/64 scope link tentative dadfailed + valid_lft forever preferred_lft forever +``` + +-------------------------------------------------------------------------------- + +via: https://www.2daygeek.com/execute-run-linux-commands-remote-system-over-ssh/ + +作者：[Magesh Maruthamuthu][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://www.2daygeek.com/author/magesh/ +[b]: https://github.com/lujun9972 +[1]: https://www.2daygeek.com/linux-check-disk-space-usage-df-command/ +[2]: https://www.2daygeek.com/how-to-configure-sudo-access-in-linux/ +[3]: https://www.2daygeek.com/linux-fdisk-command-to-manage-disk-partitions/ +[4]: https://www.2daygeek.com/four-methods-to-change-the-hostname-in-linux/ +[5]: https://www.2daygeek.com/understanding-linux-top-command-output-usage/ +[6]: https://www.2daygeek.com/category/shell-script/ +[7]: https://www.2daygeek.com/pssh-parallel-ssh-run-execute-commands-on-multiple-linux-servers/ +[8]: https://www.2daygeek.com/clustershell-clush-run-commands-on-cluster-nodes-remote-system-in-parallel-linux/ +[9]: https://www.2daygeek.com/dsh-run-execute-shell-commands-on-multiple-linux-servers-at-once/ +[10]: https://www.2daygeek.com/configure-setup-passwordless-ssh-key-based-authentication-linux/