Wolfram Schneider 1efb053dc4 option -f and -i are exclusive
all flag variables initialized with zero
respond `Y' is equal to `y'
update usage string
prompt only if source exist

ignore -i option if file descriptor stdin not refers to a valid
terminal type device
1996-02-18 18:44:58 +00:00
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1996-02-18 18:44:58 +00:00
1996-02-18 18:44:58 +00:00