Elvish 0.21.0 has been released on 2024-08-14, six months after 0.20.0, bringing new features and bugfixes.

As usual, prebuilt binaries are offered for most common platforms.

Notable new features

A new with command for running a lambda with temporary assignments.
A new keep-if command.
The os module has gained the following new commands: mkdir-all, symlink and rename.
A new render-styledown command.
A new str:repeat command.
A new md module, currently containing a single function md:show for rendering Markdown in the terminal.
On Unix, Elvish now turns off output flow control (IXON) by default, freeing up Ctrl-S and Ctrl-Q for keybindings.

Users who require this feature can turn it back on by running stty ixon.

Notable bugfixes

The string comparison commands <s, <=s, ==s, >s and >=s (but not !=s) now accept any number of arguments, as they are documented to do.
Temporary assignments now work correctly on map and list elements (#1515).
The terminal line editor is now more aggressive in suppressing compilation errors caused by the code not being complete.

For example, during the process of typing out echo $pid, the editor no longer complains that $p is undefined when the user has typed echo $p.

The eawk command, deprecated since 0.20.0, has been removed. Use re:awk instead.
Support for the legacy ~/.elvish directory, deprecated since 0.16.0, has been removed. For the supported directory paths, see documentation for the Elvish command.
Support for the legacy temporary assignment syntax (a=b command), deprecated since 0.18.0, has been removed.

Use either the tmp command (available since 0.18.0) or the with command (available since this release) instead.
The commands !=, !=s and not-eq now only accepts two arguments (#1767).
The commands edit:kill-left-alnum-word and edit:kill-right-alnum-word have been renamed to edit:kill-alnum-word-left and edit:kill-alnum-word-right, to be consistent with the documentation and the names of other similar commands.

If you need to write code that supports both names, use has-key to detect which name is available:
```
fn kill-alnum-word-left {
    if (has-key edit: kill-alnum-word-left~) {
        edit:kill-alnum-word-left
    } else {
        edit:kill-left-alnum-word
    }
}
```
Using else without catch in the try special command is no longer supported. The command try { a } else { b } finally { c } is equivalent to just try { a; b } finally { c }.