1. watchexec(1)
3. watchexec(1)

NAME

watchexec - execute commands when watched files change

SYNOPSIS

watchexec [OPTIONS] [--] command [argument...] watchexec -V|--version watchexec [-h|--help]

DESCRIPTION

Recursively monitors the current directory for changes, executing the command when a filesystem change is detected. By default, watchexec uses efficient kernel-level mechanisms to watch for changes.

At startup, the specified command (passing any supplied arguments) is run once, and watchexec begins monitoring for changes.

OPTIONS

Command options

command

Command to run when watched files are modified, and at startup, unless --postpone is specified. All arguments are passed to command. If you pass flags to the command, you should separate it with --, for example: watchexec -w src -- rsync -a src dest.

Behaviour depends on the value of --shell: for all except none, every part of command is joined together into one string with a single ascii space character, and given to the shell as described. For none, each distinct element of command is passed as per the execvp(3) convention: first argument is the program, as a file or searched in the PATH, rest are arguments.

-E, --env key=value pair

Set additional environment variables on the command (not to Watchexec itself). Can be given multiple times (one per variable to set).

-n

Shorthand for --shell=none.

--no-process-group

Do not use a process group when running command.

--no-environment

Do not set WATCHEXEC*PATH environment variables for the command.

--no-shell

Deprecated. Alias for --shell=none.

--shell shell

Change the shell used to run the command. Set to none to run the command directly without a shell.

The special value powershell will use Microsoft Powershell's calling convention, otherwise SHELL -c COMMAND.

On Windows, the additional cmd special value uses CMD.EXE calling convention.

The none value is especially useful in combination with --signal, as the signal is then sent directly to the running command. While --shell=none is a little more performant than the default, it prevents using shell-features like pipes and redirects.

If not a special value, the string provided may contain arguments to the shell as long as that is kept simple: the string is split along whitespace, and used as per execvp(3): first is shell program, rest are arguments to the shell, then -c is added, and finally the COMMAND.

See the EXAMPLES for uses of each of these.

--workdir <path>

Set the working directory of the command (not of Watchexec itself!). By default not set, and inherited from the Watchexec instance as is usual.

Filtering options

-e, --exts extensions

Comma-separated list of file extensions to filter by. Leading dots (.rs) are allowed. (This is a shorthand for -f).

-f, --filter pattern

Ignores modifications from paths that do not match pattern. This option can be specified multiple times, where a match on any given pattern causes the path to trigger command.

-i, --ignore pattern

Ignores modifications from paths that match pattern. This option can be specified multiple times, and a match on any pattern causes the path to be ignored.

--no-default-ignore

Skip default ignore statements. By default, watchexec ignores common temporary files for you, for example *.swp, *.pyc, and .DS_Store, as well as the data directories of known VCS: .bzr, _darcs, .fossil-settings, .git, .hg, .pijul, and .svn.

--no-global-ignore

Skip loading of global ignore files. By default, watchexec loads $HOME/.gitignore and other such global files and uses them to filter change events.

--no-meta

Ignore metadata changes.

--no-project-ignore, --no-ignore (deprecated alias)

Skip loading of project-local ignore files (include VCS ignore files). By default, watchexec loads .ignore, .gitignore, .hgignore, and other such files in the current directory (or child directories as applicable) and uses them to filter change events.

The --no-ignore alias will be replaced by a new option in 2.0.0, beware!

--no-vcs-ignore

Skip loading of version control system (VCS) ignore files. By default, watchexec loads .gitignore, .hgignore, and other such files in the current directory (or child directories as applicable) and uses them to filter change events.

--project-origin path

Overrides the project origin, where ignore files are resolved from (see PATHS section below).

-w, --watch path

Monitor a specific path for changes. By default, the current working directory is watched. This may be specified multiple times, where a change in any watched directory (and subdirectories) causes command to be executed.

Behaviour options

-d, --debounce

Set the timeout between detected change and command execution, to avoid restarting too frequently when there are many events; defaults to 100ms.

--force-poll interval

Poll for changes every interval ms instead of using system-specific notification mechanisms (such as inotify). This is useful when you are monitoring NFS shares.

-p, --postpone

Postpone execution of command until the first file modification is detected.

-r, --restart

Terminates the command if it is still running when subsequent file modifications are detected. By default, sends SIGTERM; use --signal to change that.

-s, --signal

Sends the specified signal (e.g. SIGKILL) to the command. Defaults to SIGTERM.

-W, --watch-when-idle

Ignore events while the process is still running. This is distinct from --restart in that with this option, events received while the command is running will not trigger a new run immediately after the current command is done.

This behaviour will become the default in v2.0.

Output options

-c, --clear

Clears the screen before executing command.

-N, --notify

Sends desktop notifications on command start and command end.

Debugging options

--print-events, --changes-only (deprecated alias)

Prints the events (changed paths, etc) that have triggered an action to STDERR.

-v, --verbose, -vv, etc

Prints diagnostic and debugging messages to STDERR. Increase the amount of vs to get progressively more output: for bug reports use three, and for deep debugging four can be helpful.

--log-file path

Writes diagnostic and debugging messages (from the -v options) to file instead of STDERR, in JSON format. This is preferrable for reporting bugs. Be careful not to write to a file within the purview of Watchexec to avoid recursion!

-V, --version

Print the version of watchexec.

-h, --help

Print a help message.

PATHS

By default, Watchexec watches the current directory. This can be changed with the --watch option, which can be passed multiple times.

Upon starting, Watchexec resolves a "project origin" from the watched paths. To do so, it recurses up every parent directory from each watched path, looking for file and directory patterns which indicate a project origin among many different software systems, such as a Git repo, Cargo crate, licensing files, readmes, workspace configuration, etc. For the full current list, consult the source at lib/src/project.rs.

Once it has a list of "potential project origins", it resolves the common prefix they all have, and uses this as the overall project origin. Note that the home directory is excluded from potential origins unless it's explicitly requested as a watched path.

The overall project origin is used to find and resolve ignore files, such that in most cases it acts as one would expect for a tool that runs anywhere inside a project.

For this reason, it is not recommended to use Watchexec for watching disparate folders in a filesystem, where those would resolve to a too-broad project origin.

The project origin can be overridden with the --project-origin option.

ENVIRONMENT

In variables that contain lists of paths, the separator is as for the $PATH environment variable (a colon, or semicolon on Windows).

Set on child processes

Processes started by watchexec have environment variables set describing the changes observed.

$WATCHEXEC_COMMON_PATH is set to the longest common path of all of the below variables, and so should be prepended to each path to obtain the full/real path. Then:

• $WATCHEXEC_CREATED_PATH is set when files/folders were created
• $WATCHEXEC_REMOVED_PATH is set when files/folders were removed
• $WATCHEXEC_RENAMED_PATH is set when files/folders were renamed
• $WATCHEXEC_WRITTEN_PATH is set when files/folders were modified
• $WATCHEXEC_META_CHANGED_PATH is set when files/folders' metadata were modified
• $WATCHEXEC_OTHERWISE_CHANGED_PATH is set for every other kind of pathed event

These variables may contain multiple paths: these are separated by the platform's path separator, as with the PATH system environment variable. On Unix that is :, and on Windows ;. Within each variable, paths are deduplicated and sorted in binary order (i.e. neither Unicode nor locale aware).

One thing to take care of is assuming inherent behaviour where there is only chance. Notably, it could appear as if the RENAMED variable contains both the original and the new path being renamed. In previous versions, it would even appear on some platforms as if the original always came before the new. However, none of this was true. It's impossible to reliably and portably know which changed path is the old or new, "half" renames may appear (only the original, only the new), "unknown" renames may appear (change was a rename, but whether it was the old or new isn't known), rename events might split across two debouncing boundaries, and so on.

This variable group can be disabled or limited with --no-environment (doesn't set any of these variables) and --no-meta (ignores metadata changes).

Read upon startup

• $WATCHEXEC_FILTERER: select the filterer implementation: globset (default), or tagged (experimental).
• $WATCHEXEC_IGNORE_FILES: a list of paths to additional ignore files to be loaded.
• $WATCHEXEC_FILTER_FILES: a list of paths to additional "Tagged" filter files to be loaded (when enabled).
• $RUST_LOG: use for advanced verbose logging configuration. Refer to tracing-subscriber for documentation.

FILES

Supported project ignore files

• Git: .gitignore at project root and child directories, .git/info/exclude, and the file pointed to by core.excludesFile in .git/config.
• Mercurial: .hgignore at project root and child directories.
• Bazaar: .bzrignore at project root.
• Darcs: _darcs/prefs/boring
• Fossil: .fossil-settings/ignore-glob
• Ripgrep/Watchexec/generic: .ignore at project root and child directories.

Note that VCS ignore files (Git, Mercurial, Bazaar, Darcs, Fossil) are only used if the corresponding VCS is discovered to be in use for the project/origin. For example, a .bzrignore in a Git repository will be discarded.

Supported global ignore files

• Git (if core.excludesFile is set): the file at that path
• Git (otherwise): the first found of $XDG_CONFIG_HOME/git/ignore, %APPDATA%/.gitignore, %USERPROFILE%/.gitignore, $HOME/.config/git/ignore, $HOME/.gitignore.
• Bazaar: the first found of %APPDATA%/Bazzar/2.0/ignore, $HOME/.bazaar/ignore.
• Watchexec: the first found of $XDG_CONFIG_HOME/watchexec/ignore, %APPDATA%/watchexec/ignore, %USERPROFILE%/.watchexec/ignore, $HOME/.watchexec/ignore.

Note that like for project files, Git and Bazaar global files will only be used for the corresponding VCS as used in the project.

EXAMPLES

Rebuild a project when source files change:

$ watchexec make

Watch all HTML, CSS, and JavaScript files for changes:

$ watchexec -e html,css,js make

Run tests when source files change, clearing the screen each time:

$ watchexec -c make test

Launch and restart a node.js server:

$ watchexec -r node app.js

Watch lib and src directories for changes, rebuilding each time:

$ watchexec -w lib -w src make

Use without shell:

$ watchexec -n -- zsh -x -o shwordsplit scr

Use with powershell (default on windows from 2.0):

$ watchexec --shell=powershell -- test-connection localhost

Use with cmd (default on windows until 2.0):

$ watchexec --shell=cmd -- dir

Use with a different unix shell:

$ watchexec --shell=bash -- 'echo $BASH_VERSION'

Use with a unix shell and options:

$ watchexec --shell='zsh -x -o shwordsplit' -- scr

2. June 2022
3. watchexec(1)