Portable OpenBSD ksh(1). Not an official OpenBSD project.

Because all operating systems deserve a good shell.

Unlike other ports of OpenBSD ksh, this port is entirely self-contained and aims to be maximally portable across operating systems and C compilers. We are always looking for new combinations to add support for.

oksh is known to run on the following Operating Systems:

• OpenBSD
• FreeBSD
• DragonFly BSD
• NetBSD
• HardenedBSD
• SoloBSD (as the default shell)
• Mac OS X (port originally by @geoff-nixon)
• Linux (glibc and musl)
• Cygwin
• Android (via Termux)
• AIX (with major thanks to @tssva and @NattyNarwhal)
• IBM i PASE
• Solaris
• Illumos
• midipix
• WSL
• WSL2
• Unixware 7
• Haiku
• HP-UX (gcc only)
• SerenityOS
• MSYS2

Running on a system not listed here? Add it and send a pull request!

We believe that oksh will work on the following platforms, but testing is needed. Help is greatly appreciated and encouraged!

• Irix

oksh is known to build with the following C compilers:

• clang
• gcc
• pcc
• cparser
• xlc
• Sun Studio compiler
• lacc
• Optimizing C Compilation System (CCS) 4.2 03/27/14 (uw714mp5.bl4s)
• Tiny C Compiler
• CompCert
• Nils Weller's C compiler
• cproc (Currently requires a small tweak to ignore a volatile store error)
• vbcc (Only tested on OpenBSD/i386)
• chibicc
• kefir

Building with a compiler not listed here? Add it and send a pull request!

oksh is included in some package systems.

In addition, there are some unofficial packages:

• Ubuntu PPA
• Debian

Using a package not listed here? Add it and send a pull request!

A C99 compiler is the easiest way to ensure that oksh will build correctly. Please see the list of C compilers above for a list of known working compilers.

Though not required, the ncurses library will be used for screen clearing routines if the library is found during the configure stage. This can be turned off by the user by passing the --disable-curses flag to configure.

A configure script that produces a POSIX Makefile is provided to ease building and installation and can be run by:

$ ./configure
$ make && sudo make install

The configure script will detect out-of-tree builds if you prefer to build out-of-tree. In order for this to work, the VPATH make extension is used. While not POSIX, VPATH is known to work with BSD make and GNU make. In-tree builds create a fully POSIX Makefile.

Cross compiling can be achieved by running configure as follows:

CC=/path/to/cross/cc CFLAGS="any needed cflags" LDFLAGS="any needed ldflags" ./configure --no-thanks

This will skip all configure checks and write out a generic Makefile and pconfig.h with nearly no options turned on. If using a cross gcc or clang, this very well may just work (with all compat compiled in). You can edit these files to reflect your system before running make.

All environment variables and configure flags are respected when using --no-thanks. Further specifying --no-link after --no-thanks will only compile the source files into object files, to be transfered onto the target machine and linked there.

The --no-thanks flag can also be used to compile a native oksh with all the compatibility functions compiled in, rather than relying on the system's version of those functions.

Patches that add new platforms and improve support for existing platforms are always welcome.

Patches that cause oksh to deviate from upstream OpenBSD ksh behavior are better suited to be sent to the OpenBSD tech@ mailing list. Please make sure to test your patch on an OpenBSD machine first before submitting it to tech@. I will sync with the upstream OpenBSD code once your patch is accepted. If you'd like to open an issue here to track progress of your patch on tech@, that's fine.

The main Korn shell files are public domain (see LEGAL). Portability files are BSD or ISC licensed; see individual file headers for details.

See releases tab. The latest release is oksh-7.5, which matches the ksh(1) from OpenBSD 7.5, released April 5, 2024.