69 lines
1.8 KiB
Groff
69 lines
1.8 KiB
Groff
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.\" Copyright (c) 2023 DTB <trinity@trinity.moe>
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.\" Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
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.\"
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.\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
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.\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
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.TH npc 1
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.SH NAME
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npc \(en show non-printing characters
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.SH SYNOPSIS
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npc
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.RB ( -eht )
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.SH DESCRIPTION
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Npc reads from standard input and writes to standard output, replacing non-
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printing characters with printable equivalents. Control characters print as a
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carat ('^') followed by the character '@' through '_' corresponding to the
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character replaced (e.g. control-X becomes "^X"). The delete character (0x7F)
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becomes "^?". Characters with the high bit set (>127) are printed as "M-"
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followed by the graphical representation for the same character without the
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high bit set.
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.PP
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The
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.B -e
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option prints a currency sign ('$') before each line ending.
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.PP
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The
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.B -t
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option prints tab characters as "^I" rather than a literal horizontal tab.
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.SH DIAGNOSTICS
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Npc prints a debug message and exits with the appropriate sysexits(3) error
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code in the event of an error, otherwise it exits successfully.
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.SH BUGS
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Npc operates in single-byte chunks regardless of intended encoding.
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.SH RATIONALE
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POSIX currently lacks a way to display non-printing characters in the terminal
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using a standard tool. A popular extension to cat(1p), the -v option, is the
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bandage solution GNU and other software suites use.
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This functionality should be a separate tool because its usefulness extends
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beyond that of cat(1p).
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.SH AUTHOR
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Written by DTB <trinity@trinity.moe>.
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.SH COPYRIGHT
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Copyright © 2023 DTB. License AGPLv3+: GNU AGPL version 3 or later
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<https://gnu.org/licenses/agpl.html>.
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.SH SEE ALSO
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cat(1), cat-v(1)
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.I UNIX Style, or cat -v Considered Harmful
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by Rob Pike
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