如何通过在machineA和machineC上运行shell脚本来执行命令

Question

I have three machines as mentioned below -

machineA
machineB
machineC

machineB and machineC has this directory -

/bat/data/snapshot_t1/

Now I need to run my below shell script from machineA and figure out the latest directory in machineB and machineC (by logging into those machine I guess) under this path /bat/data/snapshot_t1/ .

Below is my shell script in which I know how to get the latest directory using find command along with sort and tail.

Now I am supposed to run the below shell script from machineA and then find out the latest directory in machineB and machineC.. How to do that?

#!/bin/bash

readonly FILERS_LOCATION=(machineB machineC)
readonly DIRECTORY_LOCATION=/bat/data/snapshot_t1/

# login to machineB and find out the latest directory in machineB
dir1=`find $DIRECTORY_LOCATION -type d | sort | tail -1`; echo $dir

# login to machineC and find out the latest directory in machineC
dir2=`find $DIRECTORY_LOCATION -type d | sort | tail -1`; echo $dir

How do I login into machineB and machineC from the shell script which is running in machineA and then execute certain commands on machineB and machineC and get the result back and store it in some variable, let's say dir1 and dir2.

Suppose the login name is david and let's say I have the keys setup as well on machineB and machineC.

Answer 1

You can copy machineA 's public key to david@machineB and david@machineC search ssh-keygen and ssh-copy-id

After you setup the keys, you can run any command from machineA without manually keying in any password. ssh david@machineB hostname

to get dir1 .

dir1=$(ssh david@machineB find $DIR -type d | sort | tail -1)

Answer 2

Use SSH to execute the command remotely and pipe the result into another program/shell script to process it. ssh user@host yourscript.sh | anotherscript.sh ssh user@host yourscript.sh | anotherscript.sh .

ssh user@host yourscript.sh executes your command on the remote machine and prints the result on stdout , so you can capture it and redirect it to a file ( ssh user@host yourscript.sh > result.txt ) to process later or directly pipe it into another script ( ssh user@host yourscript.sh | anotherscript.sh ).

You can check $? variable for the exit status of the remote command.

Answer 3

you can use ssh

command is ssh -p port_num user@host

port_num is the port number by default it is 22 . user is the userName host is the ip or hostName .