--- title: "`deno repl`, interactive scripting prompt" oldUrl: /runtime/manual/tools/repl/ command: repl openGraphLayout: "/open_graph/cli-commands.jsx" openGraphTitle: "deno repl" description: "Interact with Deno's runtime in a REPL environment" --- ## Special variables The REPL provides a couple of special variables, that are always available: | Identifier | Description | | ---------- | ------------------------------------ | | _ | Yields the last evaluated expression | | _error | Yields the last thrown error | ```console Deno 1.14.3 exit using ctrl+d or close() > "hello world!" "hello world!" > _ "hello world!" > const foo = "bar"; undefined > _ undefined ``` ## Special functions The REPL provides several functions in the global scope: | Function | Description | | -------- | --------------------------------- | | clear() | Clears the entire terminal screen | | close() | Close the current REPL session | ## `--eval` flag `--eval` flag allows you to run some code in the runtime before you are dropped into the REPL. This is useful for importing some code you commonly use in the REPL, or modifying the runtime in some way: ```console $ deno repl --allow-net --eval 'import { assert } from "jsr:@std/assert@1"' Deno 1.45.3 exit using ctrl+d, ctrl+c, or close() > assert(true) undefined > assert(false) Uncaught AssertionError at assert (https://jsr.io/@std/assert/1.0.0/assert.ts:21:11) at :1:22 ``` ## `--eval-file` flag `--eval-file` flag allows you to run code from specified files before you are dropped into the REPL. Like the `--eval` flag, this is useful for importing code you commonly use in the REPL, or modifying the runtime in some way. Files can be specified as paths or URLs. URL files are cached and can be reloaded via the `--reload` flag. If `--eval` is also specified, then `--eval-file` files are run before the `--eval` code. ```console $ deno repl --eval-file=https://docs.deno.com/examples/welcome.ts,https://docs.deno.com/examples/local.ts Download https://docs.deno.com/examples/welcome.ts Welcome to Deno! Download https://docs.deno.com/examples/local.ts Deno 1.45.3 exit using ctrl+d or close() > local // this variable is defined locally in local.ts, but not exported "This is a local variable inside of local.ts" ``` ### Relative Import Path Resolution If `--eval-file` specifies a code file that contains relative imports, then the runtime will try to resolve the imports relative to the current working directory. It will not try to resolve them relative to the code file's location. This can cause "Module not found" errors when `--eval-file` is used with module files: ```console $ deno repl --eval-file=https://jsr.io/@std/encoding/1.0.0/ascii85.ts error in --eval-file file https://jsr.io/@std/encoding/1.0.0/ascii85.ts. Uncaught TypeError: Module not found "file:///home/_validate_binary_like.ts". at async :2:13 Deno 1.45.3 exit using ctrl+d or close() > ``` ## Tab completions Tab completions are crucial feature for quick navigation in REPL. After hitting `tab` key, Deno will now show a list of all possible completions. ```console $ deno repl Deno 1.45.3 exit using ctrl+d or close() > Deno.read readTextFile readFile readDirSync readLinkSync readAll read readTextFileSync readFileSync readDir readLink readAllSync readSync ``` ## Keyboard shortcuts | Keystroke | Action | | --------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Ctrl-A, Home | Move cursor to the beginning of line | | Ctrl-B, Left | Move cursor one character left | | Ctrl-C | Interrupt and cancel the current edit | | Ctrl-D | If line _is_ empty, signal end of line | | Ctrl-D, Del | If line is _not_ empty, delete character under cursor | | Ctrl-E, End | Move cursor to end of line | | Ctrl-F, Right | Move cursor one character right | | Ctrl-H, Backspace | Delete character before cursor | | Ctrl-I, Tab | Next completion | | Ctrl-J, Ctrl-M, Enter | Finish the line entry | | Ctrl-K | Delete from cursor to end of line | | Ctrl-L | Clear screen | | Ctrl-N, Down | Next match from history | | Ctrl-P, Up | Previous match from history | | Ctrl-R | Reverse Search history (Ctrl-S forward, Ctrl-G cancel) | | Ctrl-T | Transpose previous character with current character | | Ctrl-U | Delete from start of line to cursor | | Ctrl-V, Ctrl-Q | Insert the subsequent character verbatim instead of performing any Action associated with it. For example, to insert a newline while editing a multi-line history entry, press Ctrl-V then Ctrl-J (Ctrl-J is the ASCII Control Character `Line Feed`) | | Ctrl-W | Delete word leading up to cursor (using white space as a word boundary) | | Ctrl-X Ctrl-U | Undo | | Ctrl-Y | Paste from Yank buffer | | Ctrl-Y | Paste from Yank buffer (Meta-Y to paste next yank instead) | | Ctrl-Z | Suspend (Unix only) | | Ctrl-_ | Undo | | Meta-0, 1, ..., - | Specify the digit to the argument. `–` starts a negative argument. | | Meta < | Move to first entry in history | | Meta > | Move to last entry in history | | Meta-B, Alt-Left | Move cursor to previous word | | Meta-Backspace | Kill from the start of the current word, or, if between words, to the start of the previous word | | Meta-C | Capitalize the current word | | Meta-D | Delete forwards one word | | Meta-F, Alt-Right | Move cursor to next word | | Meta-L | Lower-case the next word | | Meta-T | Transpose words | | Meta-U | Upper-case the next word | | Meta-Y | See Ctrl-Y | | Ctrl-S | Insert a new line | ## `DENO_REPL_HISTORY` By default, Deno stores REPL history in a `deno_history.txt` file within the `DENO_DIR` directory. The location of your `DENO_DIR` directory and other resources, can be found by running the `deno info`. You can use `DENO_REPL_HISTORY` environmental variable to control where Deno stores the REPL history file. You can set it to an empty value, Deno will not store the history file.