It is often more convenient to save perl program files with . . . . . . . . extension.

A. ^pat B. $pat C. pat$ D. pat^ E. None of the above

A. sort B. sh C. st D. sort -r E. None of the above

A. cat B. head C. more D. grep E. None of the above

A. cp chap?? progs B. cp chap* progs C. cp chap[12] /progs/*.* D. cp chap?? /progs/* E. None of the above