Linux: cómo ejecutar comandos en un servidor remoto

En algunos casos, necesitamos ejecutar comandos en un servidor remoto.
Ejemplos:

Obtener información del disco
Obtener todo el proceso en ejecución
...

Sintaxis para ejecutar comandos en un servidor remoto:

1	ssh [USER@][HOSTNAME-OR-IP] command

Opciones completas:

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[root@tutorialspots ~]# ssh usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]            [-D [bind_address:]port] [-E log_file] [-e escape_char]            [-F configfile] [-I pkcs11] [-i identity_file]            [-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]            [-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]            [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]            [user@]hostname [command]

Ejemplo 1: obtener información del disco

1	ssh root@tutorialspots.com df -h

Resultado:

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[root@tutorialspots ~]# ssh root@tutorialspots.com df -h The authenticity of host 'tutorialspots.com (51.91.115.214)' can't be established. ECDSA key fingerprint is SHA256:yxg/X3UwKkrQWI8LoQdmerXPgr6IMM2mc2XxRpPpslk. ECDSA key fingerprint is MD5:86:09:6d:c1:05:1f:e0:e7:04:6c:6f:33:8d:7a:9e:33. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'tutorialspots.com' (ECDSA) to the list of known hosts. root@tutorialspots.com's password: Filesystem      Size  Used Avail Use% Mounted on devtmpfs         16G     0   16G   0% /dev tmpfs            16G     0   16G   0% /dev/shm tmpfs            16G  556K   16G   1% /run tmpfs            16G     0   16G   0% /sys/fs/cgroup /dev/md2        5.4T  1.6T  3.6T  31% / /dev/md1        487M  148M  314M  32% /boot tmpfs           3.2G     0  3.2G   0% /run/user/0

Para omitir la verificación estricta de HostKey:

1	ssh -o StrictHostKeyChecking=no root@tutorialspots.com df -h

Ejemplo 2: comprobar el promedio de carga

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[root@tutorialspots ~]# ssh root@tutorialspots.com cat /proc/loadavg root@tutorialspots.com's password: 0.75 0.52 0.58 1/296 15713

Si desea utilizar la contraseña en la línea de comandos, debe instalar sshpass:

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[root@tutorialspots ~]# yum install -y sshpass Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile epel/x86_64/metalink                                     |  13 kB     00:00  * base: linux.darkpenguin.net  * epel: mirror.imt-systems.com  * extras: mirror.checkdomain.de  * updates: mirror.fra10.de.leaseweb.net base                                                     | 3.6 kB     00:00 epel                                                     | 4.7 kB     00:00 extras                                                   | 2.9 kB     00:00 ius                                                      | 1.3 kB     00:00 nodesource                                               | 2.5 kB     00:00 updates                                                  | 2.9 kB     00:00 (1/3): updates/7/x86_64/primary_db                         | 2.9 MB   00:00 (2/3): epel/x86_64/primary_db                              | 6.8 MB   00:00 (3/3): epel/x86_64/updateinfo                              | 1.0 MB   00:00 Resolving Dependencies --> Running transaction check ---> Package sshpass.x86_64 0:1.06-2.el7 will be installed --> Finished Dependency Resolution   Dependencies Resolved   ================================================================================  Package           Arch             Version              Repository        Size ================================================================================ Installing:  sshpass           x86_64           1.06-2.el7           extras            21 k   Transaction Summary ================================================================================ Install  1 Package   Total download size: 21 k Installed size: 38 k Downloading packages: sshpass-1.06-2.el7.x86_64.rpm                              |  21 kB   00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction   Installing : sshpass-1.06-2.el7.x86_64                                    1/1   Verifying  : sshpass-1.06-2.el7.x86_64                                    1/1   Installed:   sshpass.x86_64 0:1.06-2.el7   Complete!

Ejemplo 3: usar contraseña en la línea de comando

1	sshpass -p yourpassword ssh -o StrictHostKeyChecking=no root@ip "free -m"

Resultado:

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[root@tutorialspots ~]# sshpass -p yourpassword ssh -o StrictHostKeyChecking=no root@tutorialspots.com 'free -m'               total        used        free      shared  buff/cache   available Mem:          31923         888         471           0       30563       30643 Swap:         32733           5       32728

Para ignorar esta advertencia:

1	Warning: Permanently added '171.19.110.177' (ECDSA) to the list of known hosts.

Siga el Ejemplo 4:
Ejemplo 4:

1	ssh -o LogLevel=quiet user@ip_or_hostname

Ejemplo completo:

1	sshpass -p yourpass ssh -o StrictHostKeyChecking=no -o LogLevel=quiet root@137.213.62.215 "cat /root/ok/okdead.txt" > /root/ok/ok2.txt