The program /bin/bash is one of many shells, which is a program that interprets command-line input.
Before the /bin/bash, you might have noticed “#!”. This is a special type of comment that tells the system which interpreter (shell) to use to evaluate the file.
Execute the specified interpreter directly
Execute the specified interpreter via theenv command
A common use of the env command is to launch interpreters, by making use of the fact that env will search $PATH for the command it is told to launch. Since the shebang line requires an absolute path to be specified, and since the location of various interpreters (perl, bash, python) may vary a lot, it is common to use: