1 .TH CAT 1
2 .SH NAME
3 cat, read \- catenate files
4 .SH SYNOPSIS
5 .B cat
6 [
7 .I file ...
8 ]
9 .br
10 .B read
11 [
12 .B -m
13 ] [
14 .B -n
15 .I nline
16 ] [
17 .I file ...
18 ]
19 .SH DESCRIPTION
20 .I Cat
21 reads each
22 .I file
23 in sequence and writes it on the standard output.
24 Thus
25 .IP
26 .L
27 cat file
28 .LP
29 prints a file and
30 .IP
31 .L
32 cat file1 file2 >file3
33 .LP
34 concatenates the first two files and places the result
35 on the third.
36 .PP
37 If no
38 .I file
39 is given,
40 .I cat 
41 reads from the standard input.
42 Output is buffered in blocks matching the input.
43 .PP
44 .I Read
45 copies to standard output exactly one line from the named
46 .IR file ,
47 default standard input.
48 It is useful in interactive
49 .IR rc (1)
50 scripts.
51 .PP
52 The
53 .B -m
54 flag causes it to continue reading and writing multiple lines until end of file;
55 .B -n
56 causes it to read no more than
57 .I nline
58 lines.
59 .PP
60 Read always executes a single
61 .B write
62 for each line of input, which can be helpful when
63 preparing input to programs that expect line-at-a-time data.
64 It never reads any more data from the input than it prints to the output.
65 .SH SOURCE
66 .B /usr/local/plan9/src/cmd/cat.c
67 .br
68 .B /usr/local/plan9/src/cmd/read.c
69 .SH SEE ALSO
70 .IR cp (1)
71 .SH DIAGNOSTICS
72 .I Read
73 exits with status
74 .B eof
75 on end of file or, in the
76 .B -n
77 case, if it doesn't read
78 .I nlines
79 lines.
80 .SH BUGS
81 Beware of
82 .L "cat a b >a"
83 and
84 .LR "cat a b >b" ,
85 which
86 destroy input files before reading them.