COLCRT(1)

💅 COLCRT — like, the manual page bestie 💅

okay so you found colcrt, a User Commands page (section 1, she's fancy), and honestly? she's a lil retro queen and I'm obsessed. let's get into it ✨

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🌸 NAME 🌸

colcrt — a filter that makes nroff output actually previewable on a CRT 🖥️💖

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🎀 SYNOPSIS 🎀

colcrt [options] [file ...]

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✨ DESCRIPTION ✨

so here's the tea, bestie 🫖: colcrt gives you virtual half-line and reverse line feed sequences for terminals that just… don't have that capability. and also for terminals where overstriking is destructive (rude of them honestly).

the way it works is so clever: half-line characters and underlining — which it turns into a dashing - — get placed on new lines in between the normal output lines. it's giving "making room for the drama" 💅

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👑 OPTIONS 👑

• -, --no-underlining — suppresses ALL underlining, periodt. this one is especially useful when you're previewing allboxed tables from tbl(1). genuinely iconic for that use case, no cap 💖
• -2, --half-lines — causes all half-lines to be printed, which effectively double spaces the output. normally a minimal space output format is used, which suppresses empty lines. but heads up: the program never suppresses two consecutive empty lines, ever, no matter what. the -2 option is useful when you're sending output to the line printer and the output has superscripts and subscripts that would otherwise be partially invisible 😭 (we don't want them ghosting us)
• -h, --help — displays help text and exits. short king of an option 🫶
• -V, --version — displays version and exits. show me your digits 💅

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🦋 HISTORY 🦋

the colcrt command appeared in 3.0BSD. vintage, lowkey a founding mother ⭐

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💀 BUGS 💀

okay so we gotta be real, she's not perfect:

• it should fold underlines onto blanks even with the - option, so that a true underline character would show. (she simply does not 😭)
• can't back up more than 102 lines. that's the limit, bestie.
• general overstriking is lost. as a special case, '|' overstruck with '-' or underline becomes '+'.
• lines are trimmed to 132 characters. so long, farewell to your extra columns 👋
• some provision should be made for processing superscripts and subscripts in documents which are already double-spaced.

fr fr, read the BUGS section before you come for her. she's doing her best 🥺

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🌈 EXAMPLES 🌈

a typical use of colcrt would be:

tbl exum2.n | nroff -ms | colcrt - | more

look at that pipeline. main character energy 🔥

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⭐ SEE ALSO ⭐

col(1), more(1), nroff(1), troff(1), ul(1)

iykyk, the whole friend group 💜

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🙈 REPORTING BUGS 🙈

for bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>. go tell them, respectfully 🎀

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🧚 AVAILABILITY 🧚

the colcrt command is part of the util-linux package, which can be downloaded from the Linux Kernel Archive at <https://www.kernel.org/pub/linux/utils/util-linux/>. she's got a home, she's got a family 💖

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okay that's the whole page!! 🍓 this diva is util-linux 2.42.4, dated 2026-09-21, and honestly she ate and left no crumbs 👑💅✨