Chapter 2. File Comparison And Merge

Command-Line Options

Comparing 2 files:

+   kdiff3 file1 file2
+

Merging 2 files:

+   kdiff3 file1 file2 -m
+   kdiff3 file1 file2 -o outputfile
+

Comparing 3 files:

+   kdiff3 file1 file2 file3
+

Merging 3 files:

+   kdiff3 file1 file2 file3 -m
+   kdiff3 file1 file2 file3 -o outputfile
+

+ Note that file1 will be treated as + base of file2 and + file3. +

Special case: Files with the same name

+If all files have the same name but are in different directories, you can +reduce typework by specifying the filename only for the first file. E.g.: +

+   kdiff3 dir1/filename dir2 dir3
+

Commandline for starting a directory comparison or merge:

This is very similar, but now it's about directories.

+   kdiff3 dir1 dir2
+   kdiff3 dir1 dir2 -o destdir
+   kdiff3 dir1 dir2 dir3
+   kdiff3 dir1 dir2 dir3 -o destdir
+

For directory comparison and merge you can continue to read here.

Other command line options

To see all available command line options type

+kdiff3 --help
+

Example output:

+Options:
+  -m, --merge               Merge the input.
+  -b, --base file           Explicit base file. For compatibility with certain tools.
+  -o, --output file         Output file. Implies -m. E.g.: -o newfile.txt
+  --out file                Output file, again. (For compatibility with certain tools.)
+  --auto                    No GUI if all conflicts are auto-solvable. (Needs -o file)
+  --qall                    Don't solve conflicts automatically. (For compatibility...)
+  --L1 alias1               Visible name replacement for input file 1 (base).
+  --L2 alias2               Visible name replacement for input file 2.
+  --L3 alias3               Visible name replacement for input file 3.
+  -L, --fname alias         Alternative visible name replacement. Supply this once for every input.
+  --cs string               Override a config setting. Use once for every setting. E.g.: --cs "AutoAdvance=1"
+  --confighelp              Show list of config settings and current values.
+  --config file             Use a different config file.
+

The option --cs allows you to adjust a configuration value that is otherwise only adjustable via the configure dialogs. +But be aware that when KDiff3 then terminates the changed value will be stored along with the other settings. +With --confighelp you can find out the names of the available items and current values.

Via --config you can specify a different config file. When you often use KDiff3 +with completely different setups this allows you to easily switch between them.

Ignorable command line options

Many people want to use KDiff3 with some version control system. +But when that version control system calls KDiff3 using command line parameters that KDiff3 doesn't recognise, then KDiff3 terminates with an error. +The integration settings allow to specify command line parameters that should be ignored by KDiff3. +They will appear in the usage help like in this example:

+  --foo                     Ignored. (User defined.)
+

Command line options to ignore:: + A list of options, separated via semicolon ';'. When one of these options appears on the commandline, + then KDiff3 will ignore it and run without reporting an error. + (Default is "u;query;html;abort").

When this isn't enough, then it is recommended to write a shell script that does the option translation.