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28 .\" @(#)vis.1 8.4 (Berkeley) 4/19/94
36 .Nd display non-printable characters in a visual format
45 utility is a filter for converting non-printable characters
46 into a visual representation.
50 the form is unique and invertible.
51 By default, all non-graphic
52 characters except space, tab, and newline are encoded.
53 A detailed description of the
54 various visual formats is given in
57 The options are as follows:
58 .Bl -tag -width indent
60 Turns off prepending of backslash before up-arrow control sequences
61 and meta characters, and disables the doubling of backslashes.
63 produces output which is neither invertible or precise, but does
64 represent a minimum of change to the input.
68 Request a format which displays a small subset of the
69 non-printable characters using C-style backslash sequences.
73 to fold output lines to
75 columns (default 80), like
78 that a hidden newline sequence is used (which is removed
79 when inverting the file back to its original form with
81 If the last character in the encoded file does not end in a newline,
82 a hidden newline sequence is appended to the output.
84 the output usable with various editors and other utilities which
85 typically do not work with partial lines.
90 Mark newlines with the visible sequence
92 followed by the newline.
94 Turns off any encoding, except for the fact that backslashes are
95 still doubled and hidden newline sequences inserted if
100 When combined with the
105 an invertible version of the
109 can be unfolded by running the output through
112 Request a format which displays non-printable characters as
113 an octal number, \eddd.
115 Only characters considered unsafe to send to a terminal are encoded.
116 This flag allows backspace, bell, and carriage return in addition
117 to the default space, tab and newline.
119 Tabs are also encoded.
121 White space (space-tab-newline) is also encoded.
132 Due to limitations in the underlying
137 does not recognize multibyte characters, and thus may consider them to be
138 non-printable when they are in fact printable (and vice versa).