I would like to verify that an external command is available or not, strictly without executing it.
I know there are several ways for executing an external command, as described here executing_external_commands.

Why i don't want to execute and check ?
Because, i wish to check commands such as rm, tar. If i want to check the rm by executing then, i should create a temporary file and for that i should whether i have permission or not and the process goes recursive.
If it is tar, it may initiate archiving a big directory. So to avoid all those things i would like to check whether a command exists, and the current user can execute it or not in effective manner.

Any good option is appreciated.
-- Sathiyamoorthy

In reply to How to find whether an external commands exists by sathiya.sw

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