UDIFF(1)

💅 UDIFF(1) — the udiff / fdiff / fsdiff glow-up 💅

okay so bestie, welcome to the Schily's USER COMMANDS corner of the manual-verse ✨ this little trio of programs is literally here to show you where two files differ, and honestly? it's giving main character energy. 🦋

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🌸 NAME 🌸

udiff, fdiff, fsdiff — shows where two files differ 🫶

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⭐ SYNOPSIS ⭐

udiff [ options ] file1 file2

fdiff [ options ] file1 file2

fsdiff [ options ] file1 file2

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💖 DESCRIPTION 💖

So udiff shows you what lines differ between two files, periodt. 💅 It supports arbitrary line lengths (yes, even the chaotic ones) and it treats binary files the same as text files — no cap.

Here's the tea though: it does not support many options or features, and there is no best match resync mechanism. BUT — and this is the iconic part — the output is typically identical to the output from the classical UNIX diff(1). slay. 🔥

If you call it as fdiff or fsdiff, the POSIX output style is used and the nmatch=# resync default value is set to 1 line. iykyk.

If you call it as fsdiff, the exit code is compatible to bdiff(1) and differences in the files still result in a zero exit code; only an error causes a non-zero exit code. This allows fsdiff to be used as a replacement for the bdiff program for SCCS. 🎀

Since the performance of udiff is only a linear function of the file size, using fsdiff speeds up SCCS with large files. literally efficiency queen. 👑

Since the differences reported by fsdiff are smaller that what bdiff reports, this helps to keep SCCS history files smaller. (yes we stan a compact history file 💀)

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🎀 the normal output (when you call it as udiff) 🎀

The normal output if called as udiff contains lines of these forms:

-------- 1 line deleted at %ld:
-------- %ld lines deleted at %ld:
-------- 1 line added at %ld:
-------- %ld lines added at %ld:
-------- 1 line changed at %ld from:
-------- %ld lines changed at %ld-%ld from:
-------- 1 line changed to %ld lines at %ld from:
-------- %ld lines changed to 1 line at %ld-%ld from:
-------- %ld lines changed to %ld lines at %ld-%ld from:
-------- to:

followed by blocks with the changed text. This is easier to read by humans than the POSIX output variant. fr fr, it's so much friendlier 🙈

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🌈 the POSIX output variant 🌈

The POSIX output variant contains lines of these forms:

n1 a n3,n4
n1,n2 d n3
n1,n2 c n3,n4

where n1 and n2 represent lines file1 and n3 and n4 represent lines in file2. These lines resemble ed(1) commands to convert file1 to file2. By exchanging a for d and reading backward, file2 can be converted to file1. As in ed, identical pairs, where n1=n2 or n3=n4, are abbreviated as a single number. 🧚

Following each of these lines come all the lines that are affected in the first file flagged by <, then all the lines that are affected in the second file flagged by >. cute little arrows, love that for them ⭐

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✨ OPTIONS ✨

• -help — Prints a short summary of the udiff options and exists. (yes, "exists" — that's literally what the page says, we're not fixing it 😭)
• -version — Prints the udiff version number string and exists.
• nmatch=# — Sets the number of matching lines to resync. If udiff is called as udiff, the default is two lines, otherwise it is one line.
• -posix — Output the differences in POSIX style instead of using udiff style.

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💜 EXIT STATUS 💜

The following exit values are returned:

0. 0 — No differences were found (udiff and fdiff only).
1. 0 — No error occurred (fsdiff only).
2. 1 — Differences were found (udiff and fdiff only).
3. other — An error occurred.

okay yes there are two different 0s and that's not a typo, it's just how the three personalities work 💀 read the parentheticals bestie, they matter!!

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🦋 NOTES 🦋

No output is generated if the files are the same. silence is golden, and also correct 🌸

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💀 BUGS 💀

None currently known. (iconic behaviour honestly, no notes 👑)

Mail bugs and suggestions to schilytools@mlists.in-berlin.de or open a ticket at https://codeberg.org/schilytools/schilytools/issues.

The mailing list archive may be found at:

https://mlists.in-berlin.de/mailman/listinfo/schilytools-mlists.in-berlin.de.

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🌟 AUTHOR 🌟

udiff was written 1985 - 2020 by Joerg Schilling and is now maintained by the schilytools project authors. 1985 to 2020?? the longevity, the commitment, we love to see it 🫶

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🔥 SOURCE DOWNLOAD 🔥

The source code for udiff is included in the schilytools project and may be retrieved from the schilytools project at Codeberg at

https://codeberg.org/schilytools/schilytools.

The download directory is

https://codeberg.org/schilytools/schilytools/releases.

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and that's the whole page bestie!! mwah 💋 this little gem is brought to you by Joerg Schilling, dated 2022/08/21, and it lives under the UDIFF(1) name in the manual — go diff something gorgeous today 🌈💖