pesubst(1)

💅 pesubst(1) — the hxtools glow-up of stream substitution ✨

okay bestie, sit DOWN, because this little hxtools baddie is about to replace sed(1) in your heart 💖

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🌸 NAME 🌸

pesubst — perl-regexp stream substitution, aka the moment your regexes stopped being mid 🧚

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✨ SYNTAX ✨

pesubst [-f] [-s pattern] [-d pattern] [-m modifiers] file...

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🦋 DESCRIPTION 🦋

so pesubst substitutes strings in streams and files, and it does it using the Perl engine — yes, THE Perl engine, the main character of regex 💅

it obsoletes sed(1) for simple substitution tasks. not me saying your fave is over, but like… it is 🙈

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🎀 OPTIONS 🎀

• -f — fill the replacement string with NULs to bring it up to the size of the original string. yes literally pad it out, she's giving consistent byte counts 👑
• -s pattern — the source pattern to search for in files. this can be any valid Perl regular expression. files get slurped in as a whole, so matching across newlines should be no problem at all (with the -ms flag). slurp slay 🍓
• -d pattern — the destination (replacement) string. this can be any valid string Perl accepts. for the deets, go read the perlre(1) manpage, she's thorough fr fr 📖
• -m modifiers — a string of modifiers to apply to the regex. see below, bestie, they're right there ⬇️

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💜 MODIFIERS 💜

• e — evaluate the right side as an expression. code brain activated 🧠
• g — replace globally, i.e., all occurrences. this is always enabled in pesubst, so don't even worry about it, she does it every time 💅
• i — do case-insensitive pattern matching. FOO? foo? FoO? all the same to her 😌
• m — treat the string as multiple lines. that is, change "^" and "$" from matching the start or end of the string to matching the start or end of any line anywhere within the string. multi-line main character energy 🌈
• o — compile pattern only once. efficiency icon ⭐
• s — treat the string as single line. that is, change "." to match any character whatsoever, even a newline, which normally it would not match. she's greedy like that 🫶
• x — extend your pattern's legibility by permitting whitespace and comments. pretty patterns, pretty mind ✨

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🔥 EXAMPLES 🔥

change all occurrences of foo (case-insensitive) to bar:

pesubst -s foo -d bar -ms myfile

change all Shell-style comments into C++ ones:

pesubst -s '^#' -d // -mm myfile

using both the "m" and "i" flags:

pesubst -s '^#INCLUDE\s+' -d '#include ' -mmi myfile.c

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👑 SEE ALSO 👑

hxtools(7), pegrep(1) — go read them, iykyk 💖

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ngl if you're out here hand-rolling sed one-liners in 2008-era tooling when pesubst exists, that's a vibe check you're failing 🙈

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and that's the whole page, bestie — brought to you by hxtools, dated 2008-02-06, no cap. go substitute something iconic 💅✨🦋