Command Line Arguments

Options on the command line overwrite stored options (from diffoniq.ini).

usage: diffoniq [options] path1 path2

The two paths can be files, directories or archives, in any combination. A path containing wildcard characters opens a directory listing filtered by that pattern.

Options are written with - or /. Every switch can carry an explicit + (on) or - (off) suffix — e.g. /n- turns line numbers off, /g s- re-enables size comparison. Single-letter switches can be bundled after one dash (-bx). For compatibility with version 1.x command lines, a value may also be attached directly to the switch letter: /t4, /od and /gs- are equivalent to -t 4, /o d and /g s-.

Comparison and display switches

/cCase insensitive compare
/bIgnore trailing blanks
/xExpand tabs before comparing
/sIgnore spaces and tabs
/aDisplay whole file (opposite of F7 Hide Matching Areas)
/nDisplay line numbers
-t 4Tab size (1–19)
-m 1Number of common margin lines

Directory comparison switches

/o n|s|e|dSort by [n]ame, [s]ize, [e]xtension or [d]ate (t is accepted as a synonym for date)
/g sIgnore size
/g tIgnore date and time
/g uIgnore subdirectories
/g iIgnore single files

Other

/read-onlyOpen this comparison read-only: editing, saving and Synchronize stay locked for this run, and the title bar shows [Read-only]. Intended for use as another program’s diff viewer (see below). The switch applies to the one invocation only — it is never stored in diffoniq.ini.
/read-only-left
/read-only-right
Lock one side only; the other stays editable. The title names the locked side. Giving both is the same as /read-only.
/no-backup
/backup
Decide for this run whether saving keeps a .BAK copy of the original, regardless of the setting in Options > Settings. Like the read-only switches this applies to the one invocation only and is never stored in diffoniq.ini — useful when a host compares into a version-controlled working tree, where the extra file would show up as untracked.
/syncHeadless folder synchronization (mirror/update)
/reportHeadless comparison report (HTML, text or JSON) written to --out <file>
/benchmarkHeadless performance benchmark of the compare engine
--version, -VShow the program version and exit
--help, -hPoint to this help topic and exit

Headless still means windowed: the shell does not wait for /sync or /report on its own — use start "" /wait or Start-Process -Wait (recipes in Scripting and AI Assistants); the output file appears only when it is complete.

Three switches of the 1.x console version — /f, /i and -w — no longer exist. They are ignored rather than reported as an error, so an old command line still opens its comparison. Anything else unknown is rejected with a message box and exit code 3 — never silently.

Using Diffoniq as another program’s diff viewer

Ready-made configuration lines for Git, TortoiseGit/TortoiseSVN, Total Commander, WinSCP and the common IDEs are collected under Using Diffoniq from Other Programs.

Started with two paths, Diffoniq opens the comparison straight away and runs until you close the window — which is exactly what version-control clients and file managers expect from an external diff viewer. Every call is its own window, so comparing several files one after another works. An unlicensed copy does not interrupt the calling program with an evaluation reminder in this mode.

Add /read-only whenever the calling program hands over temporary copiesgit difftool and the Tortoise clients extract the compared revision to a temp file and delete it as soon as Diffoniq closes. Without the switch you could edit and save such a side, and your changes would disappear with the temp file. With it, both sides are locked.

Often only one side is temporary. Comparing against the working tree, git difftool passes the extracted revision as the left path and your real working file as the right one — there, /read-only-left protects the temp copy while you can still edit and save your working file. A file manager such as Total Commander, by contrast, passes two real files: leave the switch away.