The Elvish Command

Table of Content:

1 Introduction

The Elvish command, elvish, contains the Elvish shell and is the main way for using the Elvish programming language. This documentation describes its behavior that is not part of the language or any of the standard modules.

2 Using Elvish interactively

Invoking Elvish with no argument runs it in interactive mode (unless there are flags that suppress this behavior).

In this mode, Elvish runs a REPL (read-eval-print loop) that evaluates input continuously. The “read” part of the REPL is a rich interactive editor, and its API is exposed by the edit: module. Each unit of code read is executed as a code chunk.

2.1 RC file

Before the REPL starts, Elvish will execute the RC file. Its path is determined as follows:

  • If the legacy ~/.elvish/rc.elv exists, it is used (this will be ignored in a future version).

  • Otherwise:

    • On UNIX (including macOS), $XDG_CONFIG_HOME/elvish/rc.elv is used, defaulting to ~/.config/elvish/rc.elv if $XDG_CONFIG_HOME is unset or empty.

    • On Windows, %AppData%\elvish\rc.elv is used.

If the RC file doesn’t exist, Elvish does not execute any RC file.

2.2 Database file

Elvish in interactive mode uses a database file to keep command and directory history. Its path is determined as follows:

  • If the legacy ~/.elvish/db exists, it is used (this will be ignored in a future version).

  • Otherwise:

    • On UNIX (including macOS), $XDG_DATA_HOME/elvish/db.bolt is used, defaulting to ~/.local/state/elvish/db.bolt if $XDG_DATA_HOME is unset or empty.

    • On Windows, %LocalAppData%\elvish\db.bolt is used.

3 Running a script

Invoking Elvish with one or more arguments will cause Elvish to execute a script (unless there are flags that suppress this behavior).

If the -c flag is given, the first argument is executed as a single code chunk.

If the -c flag is not given, the first argument is taken as a filename, and the content of the file is executed as a single code chunk.

The remaining arguments are put in $args.

4 Module search directories

When importing modules, Elvish searches the following directories:

  • On UNIX:

    1. $XDG_CONFIG_HOME/elvish/lib, defaulting to ~/.config/elvish/lib if $XDG_CONFIG_HOME is unset or empty;

    2. $XDG_DATA_HOME/elvish/lib, defaulting to ~/.local/share/elvish/lib if $XDG_DATA_HOME is unset or empty;

    3. Paths specified in the colon-delimited $XDG_DATA_DIRS, followed by elvish/lib, defaulting to /usr/local/share/elvish/lib and /usr/share/elvish/lib if $XDG_DATA_DIRS is unset or empty.

  • On Windows: %AppData%\elvish\lib, followed by %LocalAppData%\elvish\lib.

If the legacy ~/.elvish/lib directory exists, it is also searched.

5 Other command-line flags

Running elvish -help lists all supported command-line flags, which are not repeated here.