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35 .\" @(#)col.1 8.1 (Berkeley) 6/29/93
43 .Nd filter reverse line feeds from input
50 filters out reverse (and half reverse) line feeds so that the output is
51 in the correct order with only forward and half forward line
52 feeds, and replaces white-space characters with tabs where possible.
53 This can be useful in processing the output of
59 reads from the standard input and writes to the standard output.
61 The options are as follows:
62 .Bl -tag -width indent
64 Do not output any backspaces, printing only the last character
65 written to each column position.
67 Forward half line feeds are permitted (``fine'' mode).
68 Normally characters printed on a half line boundary are printed
69 on the following line.
71 Don't output multiple spaces instead of tabs (default).
73 Force unknown control sequences to be passed through unchanged.
76 will filter out any control sequences from the input other than those
77 recognized and interpreted by itself, which are listed below.
79 Output multiple spaces instead of tabs.
84 By default, 128 lines are buffered.
87 The control sequences for carriage motion that
89 understands and their decimal values are listed in the following
92 .Bl -tag -width "carriage return" -compact
94 reverse line feed (escape then 7)
96 half reverse line feed (escape then 8)
98 half forward line feed (escape then 9)
100 moves back one column (8); ignored in the first column
104 forward line feed (10); also does carriage return
106 shift to normal character set (15)
108 shift to alternate character set (14)
110 moves forward one column (32)
112 moves forward to next tab stop (9)
114 reverse line feed (11)
117 All unrecognized control characters and escape sequences are
121 keeps track of the character set as characters are read and makes
122 sure the character set is correct when they are output.
124 If the input attempts to back up to the last flushed line,
126 will display a warning message.