using a variable in a BASH command?

Question

I have 20 machines, each running a process. The machines are named:

["machine1", "machine2", ...., "machine20"]

To inspect how the process is doing on machine1, I issue the following command from a remote machine:

ssh machine1 cat log.txt

For machine2, I issue the following command:

ssh machine2 cat log.txt

Similarly, for machine20, I issue the following command:

ssh machine20 cat log.txt

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Is there a bash command that will allow me to view the output from all machines using one command?

Answer 1

If the machines are nicely numbered like in your example:

for i in {1..20} ; do ssh machine$i cat log.txt; done

If you have the list of machines in a file, you can use:

cat machinesList.txt | xargs -i ssh {} cat log.txt