Note: Links marked like this one to the mksh IRC channel connect to external resources.

⚠ Notice: the website will have the latest version of the mksh FAQ online.

# Table of Contents

- How do you spell `mksh`? How do you pronounce it?
- I’m a $OS (Android, OS/2, …) user, so what’s mksh?
- I’m an OS/2 user, what else do I need to know?
- How does this relate to ksh or the Korn Shell?
- How should I package mksh? (common cases)
- How does mksh load configuration files?
- The testsuite fails!
- I forbid stat(2) in my SELinux policy, and some things do not work!
- Why doesn’t this use a Makefile to build?
- Why do other BSDs and QNX still use pdksh instead of mksh?
- Why is there no mksh in OpenBSD’s ports tree?
- I’d like an introduction.
- My prompt from <some other shell> does not work!
- My prompt is weird!
- On startup files and `$ENV` across and detecting various shells
- ^L (Ctrl-L) does not clear the screen
- ^U (Ctrl-U) clears the entire line
- Cursor Up behaves differently from zsh
- Can mksh set the title of the window according to the command running?
- How do I start mksh on a specific terminal?
- What about programmable tab completion?
- How POSIX compliant is mksh? Also, UTF-8 vs. locales?
- What differences in function-local scopes are there?
- I get an error in this regex comparison
- Are there any extensions to avoid?
- Something is going wrong with my while...read loop
- “command” doesn’t expand aliases as in ksh93
- “rename” doesn’t work as expected!
- “sleep” does not accept ‘m’ for minutes!
- “+=” behaves differently from other shells
- I use “set -e” and my code unexpectedly errors out
- I use “set -eo pipefail” and my code unexpectedly errors out
- My question is not answered here!
- How do I contact you (to say thanks)?

# Frequently Asked Questions

## How do you spell `mksh`? How do you pronounce it?

This shell is spelt either “`mksh`” (with, even at the beginning of a sentence, an initial lowercase letter; this is important) or “MirBSD Korn Shell”, possibly with “the”.

I usually pronounce it as “em-ka-es-ha”, that is, the letters individually in my native German, or say “MirBSD Korn Shell”, although it is manageable, mostly for Slavic speakers, to actually say “mksh” as if it were a word ☺

Oh… I’ve run into this one, didn’t I? “MirBSD” is pronounced “Mir-Be-Es-De” germanically, for anglophones “Mir-beas’tie” is fine.

## I’m a $OS (Android, OS/2, …) user, so what’s mksh?

mksh is a so-called (Unix) “shell” or “command interpreter”, similar to `COMMAND.COM`, `CMD.EXE` or PowerShell on other operating systems you might know. Basically, it runs in a terminal (“console” or “DOS box”) window, taking user input and running that as commands. It’s also used to write so-called (shell) “script”s, short programs made by putting several of those commands into a “batch file”.

On Android, mksh is used as the system shell — basically, the one running commands at system startup, in the background, and on user behalf (but never of its own). Any privilege pop-ups you might be encountering are therefore not caused by mksh but by some other code invoking mksh to do something on its behalf.

## I’m an OS/2 user, what else do I need to know?

Unlike the native command prompt, the current working directory is, for security reasons common on Unix systems which the shell is designed for, not in the search path at all; if you really need this, run the command `PATH=.$PATHSEP$PATH` or add that to a suitable initialisation file (`~/.mkshrc`).

There are two different newline modes for mksh-os2: standard (Unix) mode, in which only LF (0A hex) is supported as line separator, and “textmode”, which also accepts ASCII newlines (CR+LF), like most other tools on OS/2, but creating an incompatibility with standard mksh. If you compiled mksh from source, you will get the standard Unix mode unless `-T` is added during compilation; however, you will most likely have gotten this shell through komh’s port on Hobbes, or from his OS/2 Factory on eComStation Korea, which uses “textmode”, though. Most OS/2 users will want to use “textmode” unless they need absolute compatibility with Unix mksh and other Unix shells and tools.

## How does this relate to ksh or the Korn Shell?

The Korn Shell (AT&T ksh) was authored by David Korn; two major flavours exist (ksh88 and ksh93), the latter having been maintained until 2012 (last formal release) and 2014 (last beta snapshot, buggy). A ksh86 did exist.

There’s now `ksh2020`, a project having restarted development around November 2017 forking the last `ksh93 v-` (beta) snapshot and continuing to develop it, presented at FOSDEM.

AT&T ksh88 is “the (original) Korn Shell”. Other implementations, of varying quality (MKS Toolkit’s MKS ksh being named as an example of the lower end, MirBSD’s mksh at the upper end). They are all not “Korn Shell” or “ksh”. However, mksh got blessed by David Korn, as long as it cannot be confused with the original Korn Shell.

The POSIX shell standard, while lacking most Korn Shell features, was largely based on AT&T ksh88, with some from the Bourne shell.

mksh is the currently active development of what started as the Public Domain Bourne Shell in the mid-1980s with ksh88-compatibl-ish extensions having been added later, making the Public Domain Korn Shell (pdksh), which, while never officially blessed, was the only way for most to get a Korn Shell-like command interpreter for AT&T’s was proprietary, closed-source code for a very long time. pdksh’s development ended in 1999, with some projects like Debian and NetBSD® creating small bug fixes (which often introduced new bugs) as part of maintenance. Around 2003, OpenBSD started cleaning up their shipped version of pdksh, removing old and compatibility code and modernising it. In 2002, development of what is now mksh started as the system shell of MirBSD, which took over almost all of OpenBSD’s cleanup, adding compatibility to other operating systems back on top of it, and after 2004, independent, massive development of bugfixes including a complete reorganisation of the way the parser works, and of new features both independent and compatible with other shells (ksh93, GNU bash, zsh, BSD csh) started and was followed by working with the group behind POSIX to fix issues both in the standard and in mksh. mksh became the system shell in several other operating systems and Linux distributions and Android and thus is likely the Korn shell, if not Unix shell, flavour with the largest user base. It has replaced pdksh in all contemporary systems except QNX, NetBSD® and OpenBSD (who continue to maintain their variant on “low flame”).

dtksh is the “Desktop Korn Shell”, a build of AT&T ksh93 with some additional built-in utilities for graphics programming (windows, menu bars, dialogue boxes, etc.) utilising Motif bindings.

MKS ksh is a proprietary reimplemention aiming for, but not quite getting close to, ksh88 compatibility.

SKsh is an AmigaOS-specific Korn Shell-lookalike by Steve Koren.

The Homepage of the `#ksh` channel on Freenode IRC contains more information about the Korn Shell in general and its flavours.

## How should I package mksh? (common cases)

Export a few environment variables, namely `CC` (the C compiler), `CPPFLAGS` (all C præprocessor definitions), `CFLAGS` (only compiler flags, no `-Dfoo` or anything!), `LDFLAGS` (for anything to pass to the C compiler while linking) and `LIBS` (appended to the linking command line after everything else. You might wish to `export LDSTATIC=-static` for a static build as well.

When cross-compiling, `CC` is the cross compiler (mksh currently does not require a compiler targetting the build system), but you must also export `TARGET_OS` to whatever system you are compiling for, e.g. “Linux”. For most operating systems, that’s just the uname(1) output. Some very rare systems also need `TARGET_OSREV`; consult the source code of `Build.sh` for details.

Create two subdirectories, say `build-mksh` and `build-lksh`. In each of them, start a compilation by issuing `sh ../Build.sh -r` followed by running the testsuite¹ via `./test.sh`. For lksh(1) add `-DMKSH_BINSHPOSIX` to `CPPFLAGS` and use `sh ../Build.sh -r -L` to compile.

See below if the testsuite fails.

Install `build-mksh/mksh` as `/bin/mksh` (or similar), `build-lksh/lksh` as `/bin/lksh` with a symlink(7) to it from `/bin/sh` (if desred), and `mksh.1` and `lksh.1` as manpages (mdoc macropackage required). Install `dot.mkshrc` either as `/etc/skel/.mkshrc` (meaning your users will have to manually resynchronise their home directories’ copies after every package upgrade) or as `/etc/mkshrc`, in which case you install a redirection script like Debian’s into `/etc/skel/.mkshrc`. You may need a summary of the licence information.

At runtime, the presence of `/bin/ed` as default history editor is recommended, as well as a manpage formatter; you can also install preformatted manpages from `build-*ksh/*ksh.cat1` if nroff(1) (or `$NROFF`) is available at build time by removing the `-r` flag from either `Build.sh` invocation.

Some shell features require the ability to create temporary files and FIFOS (cf. mkfifo(2))/pipes at runtime. Set `TMPDIR` to a suitable location if `/tmp` isn’t it; if this is known ahead of time, you can add `-DMKSH_DEFAULT_TMPDIR=\"/path/to/tmp\"` to CPPFLAGS. We currently are unable to determine one on Android because its bionic libc does not expose any method suitable to do so in the generic case.

① To run the testsuite, ed(1) must be available as `/bin/ed`, and perl(1) is needed. When cross-compiling, the version of the first `ed` binary on the `PATH` must be the same as that in the target system on which the tests are to be run, in order to be able to detect which flavour of ed to adjust the tests for. Busybox ed is broken beyond repair, and all three ed-related tests will always fail with it.

## How does mksh load configuration files?

The shell loads first `/etc/profile` then `~/.profile` if called as login shell or with the `-l` flag, then loads the file `$ENV` points to (defaulting to `~/.mkshrc`) for interactive shells (that includes login shells).

Distributors should take care to either install the `dot.mkshrc` example provided into `/etc/skel/.mkshrc` (so that it’s available for newly created user accounts) and ensure it can propagate to existing accounts or, if upgrading these is difficult, install the shipped file as, for example, `/etc/mkshrc` and install a skeleton file, such as the one in Debian, that sources the file in `/etc`.

It’s vital that users can change the configuration, so do not force a root-provided config file onto them; the shipped file, after all, is just an example.

If you need central user and configuration management and cannot use something that installs skeleton files upon home directory creation (like pam_mkhomedir), you can `export ENV` in `/etc/profile` to a file (say `/etc/shellrc`) that sources the per-shell file. Users can, this way, still override it by setting a different `$ENV` in their `~/.profile`.

## The testsuite fails!

The mksh testsuite has uncovered numerous bugs in operating systems (kernels, libraries), compilers and toolchains. It is likely that you just ran into one. If you’re using LTO (the `Build.sh` option `-c lto`) try to disable it first — especially GCC is a repeat offender breaking LTO and its antecessor `-fwhole-program --combine` and tends to do wrong code generation quite a bit. Otherwise, try lowering the optimisation levels, bisecting, etc.

## I forbid stat(2) in my SELinux policy, and some things do not work!

Don’t break Unix. Read up on the GIGO principle. Duh.

## Why doesn’t this use a Makefile to build?

Not all supported target operating environments have a make utility available, and shell was required for “mirtoconf” (like autoconf) already anyway, so it was chosen to run the make part as well.

You can, however, add the `-M` flag to your `Build.sh` invocations to let it produce a `Makefrag.inc` file tailored for this specific build which you can then include in a Makefile, such as with the BSD make(1) “.include” command or GNU make equivalent. It even contains, for the user to start out with, a commented-out example of how to do that in the most basic manner.

## Why do other BSDs and QNX still use pdksh instead of mksh?

Some systems are resistent to change, mostly due to bikeshedding (some people would, for example, rather see all shells banned to ports/pkgsrc®) and hysterial raisins (historical reasons ☻). Most BSDs have mksh packages available, and it works on all of them and QNX just fine.

In fact, on all of these systems, you can replace their 1999-era `/bin/ksh` (which is a pdksh) with mksh. On at least NetBSD® 1.6 and up (not 1.5) and OpenBSD, even `/bin/sh` is fair game.

MidnightBSD notably has adopted mksh as system shell (thanks laffer1).

## Why is there no mksh in OpenBSD’s ports tree?

OpenBSD don’t like people who fork off their project at all; heck, they don’t even like the people they themselves forked off (NetBSD®). Several people tried over the years to get one committed, but nobody dared so as to not lose their commit bit. If you try, succeed, and survive Theo, however, kudos to you! See also the “other BSDs” FAQ entry.

## I’d like an introduction.

Unfortunately, nobody has written a book about mksh yet, although other shells have received (sometimes decent) attention from authors and publishers. This FAQ lists a subset of things packagers and generic people ask, and the mksh(1) manpage is more of a reference, so you are probably best off starting with a shell-agnostic, POSIX or ksh88 reference such as the first edition (the second one deals with ksh93 which differs far more from mksh than ksh88, as ancient as it is, does) of the O’Reilly book (⚠ disclaimer: only an example, not a recommendation) and going forward by reading scripts (the “shellsnippets” repository referenced in the `#ksh` channel homepage (see the top of this document) has many examples) and trying to understand them and the mksh specifics from the manpage.

## My prompt from <some other shell> does not work!

Contact us on the mailing list or on IRC, we’ll convert it for you. Also have a look at the PS1 section in the mksh(1) manpage (search for “otherwise unused char”, e.g. with `/` in less(1), to spot it quickly).

## My prompt is weird!

There are several reasons why your `PS1` might be not what you’d expect:

- `$PS1` is `export`ed. Do not export PS1! (This was agreed upon as suggestion in a discussion between bash, zsh and Korn shell developers.) The feature set of different shells vastly differs and each shell should use its default PS1 or from its startup files.
- `$ENV` is set and/or `export`ed.
- Your prompt is just “`#` ”: you’re entering a root shell, and `$PS1` does not contain the ‘#’ character, in which case the shell forces this prompt, making extra privileges obvious.
- Your prompt is just “`$` ”: perhaps your system administrator did not install the shipped `dot.mkshrc` file, or you did not copy `/etc/skel/.mkshrc` into your home directory (perhaps it was created before `mksh` was installed?). Without another idea for a fix, get this file and store it as `~/.mkshrc` then run `mksh`; this will at the very least install our sample (“user@host:path $ ”) prompt.
- Your prompt contains things like “\u” or “\w”: it is for another shell and needs converting.
- Your prompt contains colours, and when the command line is long the cursor position or screen contents, especially using the history, is off: terminal escapes must be escaped from the shell; check the PS1 section in the manpage: search for “otherwise unused char” (see above).
- If the prompt doesn’t leave enough space on the right, the shell inserts a line break after it when rendering.

## On startup files and `$ENV` across and detecting various shells

Interactive shells look at `~/.mkshrc` (or `/system/etc/mkshrc` on Android and `/etc/mkshrc` on FreeWRT and OpenWrt) by default. This location can, however, be overridden by setting the `ENV` environment variable. (FreeBSD is rumoured to set it in their system profile.) It’s better to not set `$ENV` if possible and let every shell user their native startup files; otherwise, you must ensure that it runs under all shells. Check `$BASH_VERSION` (GNU bash), `$KSH_VERSION` (contains “LEGACY KSH” or “MIRBSD KSH” for mksh, “PD KSH” for ancient mirbsdksh/oksh/pdksh, “Version” for ksh93); `$NETBSD_SHELL` (NetBSD ash); `POSH_VERSION` (posh, a pdksh derivative); `$SH_VERSION` (“PD KSH” as sh), `$YASH_VERSION` (yash), `$ZSH_VERSION` (or if `$VERSION` begins with “zsh”); a list of more approaches exists.

## ^L (Ctrl-L) does not clear the screen

Use ^[^L (Escape+Ctrl-L) or rebind it:
`bind '^L=clear-screen'`

## ^U (Ctrl-U) clears the entire line

If it should only delete the line up to the cursor, use:
`bind -m ^U='^[0^K'`

## Cursor Up behaves differently from zsh

Some shells make Cursor Up search in the history only for commands starting with what was already entered. mksh separates the shortcuts: Cursor Up goes up one command and PgUp searches the history as described above. You can, of course, rebind:
`bind '^XA=search-history-up'`

## Can mksh set the title of the window according to the command running?

There’s no such thing as “the command currently running”; consider pipelines and delays (`cmd1 | (cmd2; sleep 3; cmd3) | cmd4`). There is, however, a way to make the shell display the command line during the time it is executed; for testing, you will need to download this script and `source` it. For merging into your `~/.mkshrc` you should first understand how it works: lines 4–18 set a `PS1` (prompt) equivalent to lines 84–96 of the stock `dot.mkshrc`, with one change: line 15 (`print >/dev/tty …`) is new, inserted just before the `return` command of the function substitution in the default prompt; this is what you’ll need to merge into your own, custom, prompt (if you have one; otherwise pull this adaption to the default one). Line 19 is the only other thing in this script rebinding the Ctrl-M key (which is normally produced by the Enter/Return key) to code that… does something crazy. This trick however does funny things with multiline commands, so if you type something out in multiple lines, for example here documents or loops press Ctrl-J instead of Enter/Return after each line including the first (at PS1) and final (at PS2) one.

## How do I start mksh on a specific terminal?

Normally: `mksh -T/dev/tty2`

However, if you want for it to return (e.g. for an embedded system rescue shell), use this on your real console device instead: `mksh -T!/dev/ttyACM0`

mksh can also daemonise (send to the background): `mksh -T- -c 'exec cdio lock'`

## What about programmable tab completion?

The shell itself provides static deterministic tab completion. However, you can use hooks like reprogramming the Tab key to a command line editor macro, and using the `evaluate-region` editor command (modulo a bugfix) together with `quote-region` and shell functions to implement a programmable completion engine. Multiple people have been considering doing so in our IRC channel; we’ll hyperlink to these engines when they are available.

## How POSIX compliant is mksh? Also, UTF-8 vs. locales?

You’ll need to use the `lksh` binary, unless your C `long` type is 32 bits wide, for POSIX-compliant arithmetic in the shell. This is because `mksh` provides consistent, wraparound-defined, 32-bit arithmetics on all platforms normally. You’ll also need to enable POSIX mode (`set -o posix`) explicitly, which also disables brace expansion upon being enabled (use `set -o braceexpand` to reenable if needed).

For the purpose of POSIX, mksh supports only the `C` locale. mksh’s `utf8-mode` (which only supports the BMP (Basic Multilingual Plane) of UCS and maps raw octets into the U+EF80‥U+EFFF wide character range; see `Arithmetic expressions` in mksh(1) for details) must stay disabled in POSIX mode (it is disabled upon enabling POSIX mode in R56+).

The following POSIX sh-compatible code toggles the `utf8-mode` option dependent on the current POSIX locale, for mksh to allow using the UTF-8 mode, within the constraints outlined above, in code portable across various shell implementations:

    	case ${KSH_VERSION:-} in
    	*MIRBSD KSH*|*LEGACY KSH*)
    		case ${LC_ALL:-${LC_CTYPE:-${LANG:-}}} in
    		*[Uu][Tt][Ff]8*|*[Uu][Tt][Ff]-8*) set -U ;;
    		*) set +U ;;
    		esac ;;
    	esac

In near future, (UTF-8) locale tracking will be implemented, though.

The shell is pretty close to POSIX, when run as `lksh -o posix` under the "C" locale it is intended to match. It does not do everything like other POSIX-compatible or ‑compliant shells, though.

## What differences in function-local scopes are there?

`mksh` has a different scope model from AT&T `ksh`, which leads to subtle differences in semantics for identical builtins. This can cause issues with a `nameref` to suddenly point to a local variable by accident. (Other common shells share mksh’s scoping model.)

GNU `bash` allows unsetting local variables; in `mksh`, doing so in a function allows back access to the global variable (actually the one in the next scope up) with the same name. The following code, when run before function definitions, changes the behaviour of `unset` to behave like other shells (the alias can be removed after the definitions):

    	case ${KSH_VERSION:-} in
    	*MIRBSD KSH*|*LEGACY KSH*)
    		function unset_compat {
    			\\builtin typeset unset_compat_x

    			for unset_compat_x in "$@"; do
    				eval "\\\\builtin unset $unset_compat_x[*]"
    			done
    		}
    		\\builtin alias unset=unset_compat
    		;;
    	esac

When a local variable is created (e.g. using `local`, `typeset`, `integer` or `\\builtin typeset`) it does not, like in other shells, inherit the value from the global (next scope up) variable with the same name; it is rather created without any value (unset but defined).

## I get an error in this regex comparison

Use extglobs instead of regexes:
`[[ foo =~ (foo|bar).*baz ]]`
… becomes…
`[[ foo = *@(foo|bar)*baz* ]]`

## Are there any extensions to avoid?

GNU `bash` supports “`&>`” (and “|&”) to redirect both stdout and stderr in one go, but this breaks POSIX and Korn Shell syntax; use POSIX redirections instead:

GNU bash | `foo |& bar |& baz &>log`
POSIX | `foo 2>&1 | bar 2>&1 | baz >log 2>&1`

## Something is going wrong with my while...read loop

Most likely, you’ve encountered the problem in which the shell runs all parts of a pipeline as subshell. The inner loop will be executed in a subshell and variable changes cannot be propagated if run in a pipeline:

    	bar | baz | while read foo; do ...; done

Note that `exit` in the inner loop will also only exit the subshell and not the original shell. Likewise, if the code is inside a function, `return` in the inner loop will only exit the subshell and won’t terminate the function.

Use co-processes instead:

    	bar | baz |&
    	while read -p foo; do ...; done
    	exec 3>&p; exec 3>&-

If `read` is run in a way such as `while read foo; do ...; done` then leading whitespace will be removed (IFS) and backslashes processed. You might want to use `while IFS= read -r foo; do ...; done` for pristine I/O.

Similarly, when using the `-a` option, use of the `-r` option might be prudent (`read -raN-1 arr <file`); the same applies for NUL-terminated lines:

    	find . -type f -print0 |& \
    	    while IFS= read -d '' -pr filename; do
    		print -r -- "found <${filename#./}>"
    	done

## “command” doesn’t expand aliases as in ksh93

This is because AT&T ksh93 ships a predefined alias enabling this:
`alias command='command '`
put this into your `~/.mkshrc` (note the space before the closing single quote)

## “rename” doesn’t work as expected!

There’s a `rename` built-in utility in mksh, which is a very thin wrapper around the rename(2) syscall. It receives two pathnames, source and destination where the first is then atomically renamed to the latter. It does not move, i.e. fails for different filesystems.

The GNU package `util-linux` has a different `rename` command. If you wish to invoke an external utility (in favour over a builtin), you can use `dot.mkshrc`’s function `enable` or put the following into your `~/.mkshrc`:

    alias rename="$(whence -p rename)"

## “sleep” does not accept ‘m’ for minutes!

mksh contains a `sleep` built-in utility, in order to be able to offer sub-second sleep to shell scripts for most platforms. (It does not exist if the platform lacks select(2) — which should be rare.)

GNU coreutils contains a sleep implementation accepting suffixed numbers. If you wish to invoke an external utility (in favour over a builtin), you can use `dot.mkshrc`’s function `enable` or put something along the following lines into `~/.mkshrc`:

    alias sleep="$(whence -p sleep)"

    timer() { sleep $(($1*60${2:++$2})); } # timer mins [secs]

    timer() {
    	local arg=${1/m/'*60+'}
    	[[ $arg = *+ ]] && arg+=0
    	sleep $(($arg)
    }

## “+=” behaves differently from other shells

In POSIX shell, “=” in code like `var=content` is a string assignment, always. You can use `var=$((content))` for an arithmetic assignment that mostly uses C language rules.

It stands to consider that the common shell extension “+=” as in `var+=content` would always do string concatenation; it does in mksh, but not in some other shells, in which, when `var` has been declared integer, addition is done instead.

You can make the code portable by using “((…))” (a.k.a. `let`) instead: `(( var += content ))` does arithmetic addition in all shells involved.

## I use “set -e” and my code unexpectedly errors out

I personally recommend people to not use “`set -e`”, as it makes error handling more difficult. However, some insist. There have been bugfixes (relative to e.g. oksh/loksh and posh) in this aspect, and the user has to make sure `$?` is always 0 ASAP even after a command that doesn’t check it.

    istwo() {
            for i in "$@"; do
                    test x"$i" = x"2" && echo two
            done
    }
    set -e
    istwo 1
    echo END

This can be fixed by either adding an explicit “`:`” (or “`true`”) after the comparison, or even…

    test x"$i" = x"2" && echo two || :

… or right after the `done` inside the function, but…

    test x"$i" != x"2" || echo two

… negating the condition and using “`||`” is preferable.

Remember that Korn shell-style functions (with `function` keyword and without parenthesēs) in AT&T ksh93 and mksh R51 and up have their own shell option scope, but while…

    function istwo {
            set +e
            …
    }

… might help in error handling, the return status of a function is still the last errorlevel inside, so an explicit true (“`:`”) or, more explicitly, “`return 0`” at its end is still needed if the caller runs under `set -e`.

## I use “set -eo pipefail” and my code unexpectedly errors out

Related to the above FAQ entry, using `set -o pipefail` makes the following construct error out:

    	set -e
    	for x in 1 2; do
    		false && echo $x
    	done | cat

This is because, while the `&&` ensures that the inner command’s failure is not taken, it sets the entire `for`‥`done` loop’s errorlevel, which is passed on by `-o pipefail`.

Invert the inner command:
`true || echo $x`

## My question is not answered here!

Do read the mksh(1) manual page. You might also wish to read the homepage of the `#ksh` IRC channel on Freenode which lists several resources for Korn or POSIX-compatible shells in general. Or, contact us (developer and users), for example via IRC.

## How do I contact you (to say thanks)?

You can say hi in the `#!/bin/mksh` channel on Freenode IRC, although a donation wouldn’t be amiss ☺ The mailing list can also be used.

# Imprint

This offline HTML page for mksh R59 2020/05/16 was automatically generated from the sources.