1 .TH LOOK 1
2 .SH NAME
3 look \- find lines in a sorted list
4 .SH SYNOPSIS
5 .B look
6 [
7 .BI -dfnixt c
8 ]
9 [
10 .I string
11 ]
12 [
13 .I file
14 ]
15 .SH DESCRIPTION
16 .I Look
17 consults a sorted
18 .I file
19 and prints all lines that begin with
20 .IR string .
21 It uses binary search.
22 .PP
23 The following options are recognized.
24 Options
25 .B dfnt
26 affect comparisons as in
27 .IR  sort (1).
28 .TP
29 .B -i
30 Interactive.
31 There is no
32 .I string
33 argument; instead
34 .I look
35 takes lines from the standard input as strings to be looked up.
36 .TP
37 .B -x
38 Exact.
39 Print only lines of the file whose key matches
40 .I string
41 exactly.
42 .TP
43 .B  -d
44 `Directory' order:
45 only letters, digits,
46 tabs and blanks participate in comparisons.
47 .TP
48 .B  -f
49 Fold.
50 Upper case letters compare equal to lower case.
51 .TP
52 .B -n
53 Numeric comparison with initial string of digits, optional minus sign,
54 and optional decimal point.
55 .TP
56 .BR -t [ \f2c\f1 ]
57 Character
58 .I c
59 terminates the sort key in the
60 .IR file .
61 By default, tab terminates the key.  If
62 .I c
63 is missing the entire line comprises the key.
64 .PP
65 If no
66 .I file
67 is specified,
68 .B /lib/words
69 is assumed, with collating sequence
70 .BR df .
71 .SH FILES
72 .B /lib/words
73 .SH SOURCE
74 .B \*9/src/cmd/look.c
75 .SH "SEE ALSO"
76 .IR sort (1), 
77 .MR grep (1)
78 .SH DIAGNOSTICS
79 The exit status is
80 .RB `` "not found" ''
81 if no match is found, and
82 .RB `` "no dictionary" ''
83 if
84 .I file
85 or the default dictionary cannot be opened.