usr.bin/sdiff/sdiff.1

.\" $OpenBSD: sdiff.1,v 1.15 2007/06/29 14:48:07 jmc Exp $
.\"
.\" Written by Raymond Lai <ray@cyth.net>.
.\" Public domain.
.\"
.Dd September 23, 2026
.Dt SDIFF 1
.Os
.Sh NAME
.Nm sdiff
.Nd side-by-side diff
.Sh SYNOPSIS
.Nm
.Op Fl abdilstHW
.Op Fl I Ar regexp
.Op Fl o Ar outfile
.Op Fl w Ar width
.Ar file1
.Ar file2
.Nm sdiff
.Fl -help
.Sh DESCRIPTION
.Nm
displays two files side by side,
with any differences between the two highlighted as follows:
new lines are marked with
.Sq \*(Gt ;
deleted lines are marked with
.Sq \*(Lt ;
and changed lines are marked with
.Sq \*(Ba .
.Pp
.Nm
can also be used to interactively merge two files,
prompting at each set of differences.
See the
.Fl o
option for an explanation.
.Pp
The options are:
.Bl -tag -width Ds
.It Fl l -left-column
Only print the left column for identical lines.
.It Fl o -output Ar outfile
Interactively merge
.Ar file1
and
.Ar file2
into
.Ar outfile .
In this mode, the user is prompted for each set of differences.
See
.Ev EDITOR
and
.Ev VISUAL ,
below,
for details of which editor, if any, is invoked.
.Pp
The commands are as follows:
.Bl -tag -width Ds
.It Cm l | 1
Choose left set of diffs.
.It Cm r | 2
Choose right set of diffs.
.It Cm s
Silent mode \(en identical lines are not printed.
.It Cm v
Verbose mode \(en identical lines are printed.
.It Cm e
Start editing an empty file, which will be merged into
.Ar outfile
upon exiting the editor.
.It Cm e Cm l
Start editing file with left set of diffs.
.It Cm e Cm r
Start editing file with right set of diffs.
.It Cm e Cm b
Start editing file with both sets of diffs.
.It Cm q
Quit
.Nm .
.El
.It Fl s -suppress-common-lines
Skip identical lines.
.It Fl w -width Ar width
Print a maximum of
.Ar width
characters on each line.
The default is 130 characters.
.It Fl -help
Print the usage message and exit.
.El
.Pp
Options passed to
.Xr diff 1
are:
.Bl -tag -width Ds
.It Fl a -text
Treat
.Ar file1
and
.Ar file2
as text files.
.It Fl b -ignore-space-change
Ignore trailing blank spaces.
.It Fl d -minimal
Minimize diff size.
.It Fl I -ignore-matching-lines Ar regexp
Ignore line changes matching
.Ar regexp .
All lines in the change must match
.Ar regexp
for the change to be ignored.
.It Fl i -ignore-case
Do a case-insensitive comparison.
.It Fl t -expand-tabs
Expand tabs to spaces.
.It Fl W -ignore-all-space
Ignore all spaces.
.It Fl B -ignore-blank-lines
Ignore blank lines.
.It Fl E -ignore-tab-expansion
Treat tabs and eight spaces as the same.
.It Fl H -speed-large-files
Assume scattered small changes in a large file.
.It Fl -ignore-file-name-case
Ignore the case of file names.
.It Fl -no-ignore-file-name-case
Do not ignore file name case.
.It Fl -strip-trailing-cr
Skip identical lines.
.It Fl -tabsize Ar NUM
Change the size of tabs (default is 8.)
.El
.Sh ENVIRONMENT
.Bl -tag -width Ds
.It Ev EDITOR , VISUAL
Specifies an editor to use with the
.Fl o
option.
If both
.Ev EDITOR
and
.Ev VISUAL
are set,
.Ev VISUAL
takes precedence.
If neither
.Ev EDITOR
nor
.Ev VISUAL
are set,
the default is
.Xr vi 1 .
.It Ev TMPDIR
Specifies a directory for temporary files to be created.
The default is
.Pa /tmp .
.El
.Sh EXIT STATUS
The
.Nm
utility exits with one of the following values:
.Pp
.Bl -tag -width Ds -offset indent -compact
.It 0
No differences were found.
.It 1
Differences were found.
.It >1
An error occurred.
.El
.Pp
The
.Fl -help
option exits with a status of 0.
.Sh SEE ALSO
.Xr cmp 1 ,
.Xr diff 1 ,
.Xr diff3 1 ,
.Xr vi 1 ,
.Xr re_format 7
.Sh AUTHORS
.Nm
was written from scratch for the public domain by
.An Ray Lai Aq Mt ray@cyth.net .
.Sh CAVEATS
Tabs are treated as anywhere from one to eight characters wide,
depending on the current column.
Terminals that treat tabs as eight characters wide will look best.