look - find lines in a sorted list look [ -dfnixt c ] [ string ] [ file ] Look consults a sorted file and prints all lines that begin with string . It uses binary search.

The following options are recognized. Options dfnt affect comparisons as in sort (1).

-i Interactive. There is no string argument; instead look takes lines from the standard input as strings to be looked up.

-x Exact. Print only lines of the file whose key matches string exactly.

-d `Directory' order: only letters, digits, tabs and blanks participate in comparisons.

-f Fold. Upper case letters compare equal to lower case.

-n Numeric comparison with initial string of digits, optional minus sign, and optional decimal point.

-t [ \f2c\f1 ] Character c terminates the sort key in the file . By default, tab terminates the key. If c is missing the entire line comprises the key.

If no file is specified, /lib/words is assumed, with collating sequence df .

/lib/words /sys/src/cmd/look.c sort (1), grep (1) The exit status is `` "not found" '' if no match is found, and `` "no dictionary" '' if file or the default dictionary cannot be opened.