Which command allows you to make a shell variable visible to subshells?

Question

Options

• Aexport $VARIABLE
• Bexport VARIABLE
• Cset $VARIABLE
• Dset VARIABLE
• Eenv VARIABLE

• A
  8% (5)
• B
  72% (44)
• C
  15% (9)
• D
  2% (1)
• E
  3% (2)

Explanation

export VARIABLE (no dollar sign) is the correct POSIX command to mark a shell variable for export to the environment of child processes (subshells). The export builtin works on the variable name, not its value, so the dollar sign is wrong in option A - export $VARIABLE would try to export whatever string the variable contains, not the variable itself.

Options C and D (set) are wrong because set configures shell options and positional parameters, not environment export; it has no role in making variables available to subshells. Option E (env VARIABLE) is a red herring - env can display environment variables or run a command in a modified environment, but env VARIABLE alone does nothing useful.

Memory tip: Think of export like exporting a label from a warehouse - you hand over the name tag, not the item itself. Since you're naming the variable, no $ prefix is needed, just as you'd write the label without unpacking the box.

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