parallel:tldr:c3284

This command executes the given command in parallel on multiple machines, specified by the variables ${machine1} and ${machine2}.

Here is a breakdown of the command structure:

• parallel: This is the command being executed, which is likely the GNU Parallel command-line utility.
• -S: This option specifies the remote machines on which the command should be executed in parallel.
• ${machine1},${machine2}: These variables define the list of machines on which the command will be executed. The exact values of ${machine1} and ${machine2} would need to be defined elsewhere in the script or command.
• ${command}: This variable specifies the command that will be executed in parallel on the specified machines. The exact value of ${command} would also need to be defined elsewhere.
• :::: This separator is used to separate the list of target machines from the list of arguments.
• ${arg1} ${arg2}: These variables represent the arguments that will be passed to the command. The exact values of ${arg1} and ${arg2} would need to be defined elsewhere in the script or command.

By combining these elements, the parallel command will execute ${command} in parallel on ${machine1} and ${machine2}, with ${arg1} and ${arg2} as the arguments.