What do the options 'a' and 'c' do when there are used with the command 'dash'? I was unable to understand what that command actually does! I have tried reading the man page but didn't exactly understand.

closed as unclear what you're asking by Jeff Schaller, RalfFriedl, thrig, DarkHeart, Romeo Ninov Sep 16 '18 at 3:17

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    @Ashish, you would help yourself by asking a better question: what did the man page on your system say for those options? Did you not understand some of those words? What did you try, what did you expect, and what actually happened? – Jeff Schaller Sep 15 '18 at 13:06

There are lots of sources of information regarding -c: it is used to run a command with a given shell, and is a standard option.

The -a option is different: shells let you assign variables, but without exporting, those values are only seen within a shell script — not by programs run from the shell (for that, you must export a shell variable, making it an environment variable). This option tells dash to eliminate the distinction between shell-variables and environment-variables. Doing that will break a lot of scripts by overriding/changing the values of environment variables which otherwise would pass unchanged to programs run from the shell (it probably was a useful feature 20+ years ago).

Both are standard options, but your mileage may yary

  • Sorry, but: No distinction between shell-variables and environment-variables is eliminated. – Isaac Sep 16 '18 at 14:32

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