Commit | Line | Data |
---|---|---|
e6817382 BJ |
1 | .TH COL 1 |
2 | .SH NAME | |
3 | col \- filter reverse line feeds | |
4 | .SH SYNOPSIS | |
5 | .B col [\|\-bfx\|] | |
6 | .SH DESCRIPTION | |
7 | .I Col | |
8 | reads the standard input and writes the standard output. | |
9 | It performs the line overlays implied by reverse line | |
10 | feeds (ESC-7 in ASCII) | |
11 | and by forward and reverse half line feeds (ESC-9 and ESC-8). | |
12 | .I Col | |
13 | is particularly useful for filtering multicolumn | |
14 | output made with the `.rt' command of | |
15 | .I nroff | |
16 | and output resulting from use of the | |
17 | .IR tbl (1) | |
18 | preprocessor. | |
19 | .PP | |
20 | Although | |
21 | .I col | |
22 | accepts half line motions in its input, it normally does not | |
23 | emit them on output. | |
24 | Instead, text that would appear between lines is moved to the next lower | |
25 | full line boundary. | |
26 | This treatment can be suppressed by the | |
27 | .B \-f | |
28 | (fine) option; in this case | |
29 | the output from | |
30 | .I col | |
31 | may contain forward half line feeds (ESC-9), but will still never contain | |
32 | either kind of reverse line motion. | |
33 | .PP | |
34 | If the | |
35 | .B \-b | |
36 | option is given, | |
37 | .I col | |
38 | assumes that the output device in use is not capable of backspacing. | |
39 | In this case, if several characters are to appear in the same place, | |
40 | only the last one read will be taken. | |
41 | .PP | |
42 | The control characters SO (ASCII code 017), | |
43 | and SI (016) are assumed | |
44 | to start and end text in an alternate character set. | |
45 | The character set (primary or alternate) associated with each printing | |
46 | character read is remembered; on output, SO and SI characters are generated | |
47 | where necessary to maintain the correct treatment of each character. | |
48 | .PP | |
49 | .I Col | |
50 | normally converts white space to tabs to shorten printing time. | |
51 | If the | |
52 | .B \-x | |
53 | option is given, this conversion is suppressed. | |
54 | .PP | |
55 | All control characters are removed from the input except space, | |
56 | backspace, | |
57 | tab, return, newline, ESC (033) followed by one of 7, 8, 9, SI, SO, and VT | |
58 | (013). | |
59 | This last character is an alternate form of full reverse line feed, for | |
60 | compatibility with some other hardware conventions. | |
61 | All other non-printing characters are ignored. | |
62 | .SH "SEE ALSO" | |
63 | troff(1), tbl(1), greek(1) | |
64 | .SH BUGS | |
65 | Can't back up more than 128 lines. | |
66 | .br | |
67 | No more than 800 characters, including backspaces, on a line. |