Fossil uses a number of environment variables and supports a number of global options. Most of these seem to be primarily documented in the source code, with the primary exception of --args which is described in the usage text printed by running fossil with no arguments at all.

Global Options

The following options are understood by the fossil command itself, and are collected before any subcommand begins processing.

--args FILENAME: Read the file FILENAME and replace these two arguments with its content. Each line of the file is assumed to be an argument unless it starts with '-' and contains a space, in which case it is assumed to be another flag and is treated as such. --args FILENAME may be used in conjunction with any other flags.

--case-sensitive BOOL: Override the case-sensitive setting, which can override the native preferences of the platform for case sensitive file names: insensitive on Windows, sensitive on Unix. There are probably odd interactions possible if you mix case sensitive and case insensitive file systems on any single platform. This option or the global setting should be used to force the case sensitivity to the most sensible condition.

--chdir DIRECTORY: Change to the named directory before processing any commands.

--comfmtflags NUMBER: Specify flags that control how check-in comments and certain other text outputs are formatted for display. The flags are individual bits in NUMBER, which must be specified in base 10:

• 0 — Uses the revised algorithm with no special handling.

• 1 — Uses the legacy algorithm, other flags are ignored.

• 2 — Trims leading and trailing carriage-returns and line-feeds where they do not materially impact pre-existing formatting (i.e. at the start of the comment string and right before line indentation).

• 4 — Trims leading and trailing spaces where they do not materially impact the pre-existing formatting (i.e. at the start of the comment string and right before line indentation).

• 8 — Attempts to break lines on word boundaries while honoring the logical line length.

• 16 — Looks for the original comment text within the text being printed. Upon matching, a new line will be emitted, thus preserving more of the pre-existing formatting.

--comment-format NUMBER: Alias for --comfmtflags NUMBER.

--errorlog ERRLOG: Name a file to which fossil will log panics, errors, and warnings.

--help: If --help is found anywhere on the command line, translate the command to fossil help cmdname where cmdname is the first argument that does not begin with a - character. If all arguments start with -, translate to fossil help argv[1] argv[2]....

--httptrace: (Sets g.fHttpTrace.) Trace outbound HTTP requests.

--localtime: Override the timeline-utc option to explicitly use local time.

--nocgi: Prevent fossil from acting as a CGI by default even if the GATEWAY_INTERFACE environment variable is set.

--no-th-hook: (Sets g.fNoThHook.) Override the th1-hooks setting and prevent any TH1 hooks from being executed.

--quiet: (Sets g.fQuiet.) Cause fossil to suppress various messages and progress indicators that would otherwise be printed.

--sqltrace: (Sets g.SqlTrace.) Implies --sqlstats. Trace certain SQLite database activity, especially showing every SQL query processed.

--sqlstats: (Sets g.fSqlStats.) Print a number of performance statistics about each SQLite database used when it is closed.

--sshtrace: (Sets g.fSshTrace.)

--ssl-identity: The fully qualified name of the file containing the client certificate and private key to use, in PEM format. It can be created by concatenating the client certificate and private key files. This identity will be presented to SSL servers to authenticate the client, in addition to the normal password authentication.

--systemtrace: (Sets g.fSystemTrace.) Trace all commands launched as sub processes.

--user LOGIN: (Sets g.zLogin) Also -U LOGIN. Set the user name used with the repository.

--utc: Override the timeline-utc option to explicitly use UTC time.

--vfs VFSNAME: Load the named VFS into SQLite.

Environment Variables

The location of the user's account-wide configuration database depends on the operating system and on the existence of various environment variables and/or files. See the discussion of the configuration database location algorithm for details.

EDITOR: Name the editor to use for check-in and stash comments. Overridden by the local or global editor setting or the VISUAL environment variable.

FOSSIL_BREAK: If set, an opportunity will be created to attach a debugger to the Fossil process prior to any significant work being performed.

FOSSIL_FORCE_TICKET_MODERATION: If set, ALL changes for tickets will be required to go through moderation (even those performed by the local interactive user via the command line). This can be useful for local (or remote) testing of the moderation subsystem and its impact on the contents and status of tickets.

FOSSIL_FORCE_WIKI_MODERATION: If set, ALL changes for wiki pages will be required to go through moderation (even those performed by the local interactive user via the command line). This can be useful for local (or remote) testing of the moderation subsystem and its impact on the contents and status of wiki pages.

FOSSIL_HOME: Location of configuration database. See the configuration database location description for additional information.

FOSSIL_USE_SEE_TEXTKEY: If set, treat the encryption key string for SEE as text to be hashed into the actual encryption key. This has no effect if Fossil was not compiled with SEE support enabled.

FOSSIL_USER: Name of the default user account if the checkout, local or global default-user setting is not present. The first environment variable found in the environment from the list FOSSIL_USER, USER, LOGNAME, and USERNAME is the user name. If none of those are set, then the default user name is "root". See the discussion of Fossil Username below for a lot more detail.

FOSSIL_SECURITY_LEVEL: If set to any of the values listed below, additional measures for password security will be enabled (also see How To Use Encrypted Repositories):

• ≥1 — Do not remember passwords.

• ≥2 — Use a scrambled matrix for password input.

FOSSIL_TCL_PATH: When Tcl stubs support is configured, point to a specific file or folder containing the version of Tcl to load at run time.

FOSSIL_TEST_DANGEROUS_IGNORE_OPEN_CHECKOUT: When set to the literal value YES_DO_IT, the test suite will relax the constraint that some tests may not run within an open checkout. This is subject to removal in the future.

FOSSIL_VFS: Name a VFS to load into SQLite.

GATEWAY_INTERFACE: If present and the --nocgi option is not, assume fossil is invoked from a web server as a CGI command, and act accordingly.

HOME: Potential location of the configuration database. See the configuration database location description for details.

HOMEDRIVE, HOMEPATH: (Windows) Location of the ~/.fossil file. The first environment variable found in the environment from the list FOSSIL_HOME, LOCALAPPDATA (Windows), APPDATA (Windows), HOMEDRIVE and HOMEPATH (Windows, used together), and HOME is used as the location of the ~/.fossil file.

HTTP_HOST: If defined, included in error log messages.

http_proxy: If the global or local settings proxy is not set, this is used as the default value for the proxy setting.

HTTP_USER_AGENT: If defined, included in error log messages.

LOCALAPPDATA: (Windows) Location of the ~/.fossil file. The first environment variable found in the environment from the list FOSSIL_HOME, LOCALAPPDATA (Windows), APPDATA (Windows), HOMEDRIVE and HOMEPATH (Windows, used together), and HOME is used as the location of the ~/.fossil file.

LOGNAME: Name of the logged in user on many Unix-like platforms. Used as the fossil user name if FOSSIL_USER is not specified. See the discussion of Fossil Username below for a lot more detail.

PATH: Used by most platforms to locate programs invoked without a fully qualified name. Explicitly used by fossil ui on certain platforms to choose the browser to launch.

PATH_INFO: If defined, included in error log messages.

QUERY_STRING: If defined, included in error log messages.

REMOTE_ADDR: If defined, included in error log messages.

REMOTE_HOST: Used by fossil http run from stunnel to identify the remote host.

REQUEST_METHOD: If defined, included in error log messages.

REQUEST_URI: If defined, included in error log messages.

SCRIPT_NAME: If defined, included in error log messages.

SSH_CONNECTION: Informs CGI processing if the remote client is SSH.

SQLITE_FORCE_PROXY_LOCKING: From sqlite3.c, 1 means force always use proxy, 0 means never use proxy, and undefined means use proxy for non-local files only.

SQLITE_TMPDIR: Names the temporary file location for SQLite. When set, this will be used instead of TMPDIR.

SYSTEMROOT: (Windows) Used to locate notepad.exe as a fall back comment editor.

TERM: If the linenoise library is used (almost certainly not on Windows), it will check TERM to verify that the interactive terminal is not named on a short list on terminals known to not work with linenoise. Linenoise is a library that provides command history and command line editing to interactive programs, and can be used in the fossil sqlite3 command.

TH1_DELETE_INTERP: Set this variable to ask fossil to explicitly delete the TH1 interpreter, if it is loaded, then check that it released all of its allocated memory, when exiting fossil. This is not strictly necessary, but makes debugging memory leaks easier. See main.c near line 386 for the code.

TH1_ENABLE_DOCS: Override the local or global setting tcl-docs to enable TH1 documents in fossil.

TH1_ENABLE_HOOKS: Override the local or global setting tcl-hooks to enable TH1 hooks in fossil.

TH1_ENABLE_TCL: Override the local or global setting tcl to enable Tcl in fossil.

TH1_TEST_ANON_CAPS: Override the default anonymous permissions used when processing the --set-anon-caps option for the test-th-eval, test-th-render, and test-th-source test commands.

TH1_TEST_USER_CAPS: Override the default user permissions used when processing the --set-user-caps option for the test-th-eval, test-th-render, and test-th-source test commands.

TMPDIR: Names the temporary file location for SQLite.

USER: Name of the logged in user on many Unix-like platforms. Used as the fossil user name if FOSSIL_USER is not specified. See the discussion of Fossil Username below for a lot more detail.

USERNAME: Name of the logged in user on Windows platforms. Used as the fossil user name if FOSSIL_USER is not specified. See the discussion of Fossil Username below for a lot more detail.

VISUAL: Name the editor to use for check-in and stash comments. Overrides the EDITOR environment variable. Overridden by the local or global editor setting.

Notes on Related Values

CGI and JSON Parameters

The JSON API implementation looks up many values in the first of several places searched. This unifies the parameter handling logic, allows the caller to choose whether to prefer URL parameters, request headers, or the POST payload, and allows the fossil json command to share most of the same logic as the /json API path. The search order is a POST payload, GET/COOKIE/non-JSON POST, JSON POST, the system environment.

See the comment above the implementation of json_getenv for some further discussion.

Comment Editor

The editor used to edit a check-in or stash comment is named by the local or global setting editor. If neither is set, then the environment variables VISUAL, and EDITOR are checked in that order.

On Windows, if no editor is named, then Notepad is used. Note that the operation will be aborted if notepad.exe is not found in the Windows folder.

On Unix-like platforms, if no editor is named, then a message is displayed on stdout, and stdin is read until a single line containing only a dot is seen.

Error logging

If logging errors to a file, fossil will include the values of the following environment variables in the error log entry if they are defined: HTTP_HOST, HTTP_USER_AGENT, PATH_INFO, QUERY_STRING, REMOTE_ADDR, REQUEST_METHOD, REQUEST_URI, and SCRIPT_NAME.

Fossil Username

In absence of any explicit setting, fossil will use the same name you logged in to your platform with, as the user name when interacting with local and remote repositories. Note that only the name is shared, fossil makes no attempt to share or leverage any platform's authentication mechanisms or passwords.

When logging in to a repository, it tries a series of sources for the user name, and the first non-blank name that succeeds is the logged in user. The order is:

1. The --user and -U command-line options.
2. If running within an open checkout (the local database is open), check in its table of values stored per open checkout for the value stored by fossil user default USERNAME.
3. The default user in the repository (setting default-user)
4. The FOSSIL_USER environment variable.
5. The USER environment variable.
6. The LOGNAME environment variable.
7. The USERNAME environment variable.
8. Check if the user can be extracted from the remote URL, if there is a remote URL.

Items 2 and 3 are both set by fossil user default USERNAME, the first within an open checkout, the second outside and using the -R REPOSITORY option to identify the repository. Both cases require that the named user be present in the repository when the default user is assigned. Although the default user is internally stored as if it were a setting named default-user, it is not accessible through the fossil set command.

Items 5, 6, and 7 cover most of the names of an environment variable set automatically by the platform with the name of the platform's logged in user for use by programs. Historically, USER comes from Unix System-V, LOGNAME from BSD, and USERNAME from Windows, but many Linux distributions will set both USER and LOGNAME for broad compatibility.

When creating a new repository, fossil needs a user name for the admin user granted the "s" permission. But since fossil generally expects that fossil new or fossil clone are used outside of any checkout (especially when run for the first time without any checkouts at all or the users's global settings database), it looks in a shorter list of places for a non-blank name. In the special case of a clone, default-user can be copied from the original, and so it can be set in the clone even before any users have been created, and in that case it will be the new admin user. If default-user is not set, then the first found environment variable from the list FOSSIL_USER, USER, LOGNAME, and USERNAME, is the user name. As a final fallback, if none of those are set, then the default user name is "root".

Configuration Database Location

Fossil keeps some information pertinent to each user in the user's configuration database file. The configuration database file includes the global settings and the list of repositories and checkouts used by fossil all.

The location of the configuration database file depends on the operating system and on the existence of various environment variables and/or files. In brief, the configuration database is usually:

• Traditional unix → "$HOME/.fossil"
• Windows → "%LOCALAPPDATA%/_fossil"
• XDG-unix → "$HOME/.config/fossil.db"

See the configuration database location algorithm discussion for full information.

SQLite VFS to use

See the SQLite documentation for an explanation of what a VFS actually is and what it does.

If the default VFS underneath SQLite is not suitable, an alternative can be selected with either the --vfs VFSNAME option or the FOSSIL_VFS environment variable. The --vfs option takes precedence.

Temporary File Location

Fossil places some temporary files in the checkout directory. Most notably, supporting files related to merge conflicts are placed in the same folder as the merge result.

Other temporary files need a different home. The rules for choosing one are complicated.

Fossil-specific code uses FOSSIL_TEMP, TEMP, and TMP, in that order. Fossil’s own test suite prepends FOSSIL_TEST_TEMP to that list.

The underlying SQLite code uses several different path sets for its temp files, depending on the platform type.

On Unix-like platforms, excepting Cygwin, SQLite first checks the environment variables SQLITE_TMPDIR and TMPDIR, in that order. If neither is defined, it falls back to a hard-coded list of paths: /var/tmp, /usr/tmp, and /tmp. If all of that fails, it uses the current working directory.

For Cygwin builds, SQLite instead uses the first defined variable in this list: SQLITE_TMPDIR, TMPDIR, TMP, TEMP, and USERPROFILE.

For native Windows builds, SQLite simply calls the OS’s GetTempPath() API. See that reference page for details.

That said, it is not unusual for utilities on all platforms to assume that TEMP or TMP point somewhere safe for temporary files.

If the identified temporary folder is not writable, then weird things will happen on all platforms.

Web browser

Occasionally, fossil wants to launch a web browser for the user, most obviously as part of the fossil ui command. In that specific case, the browser is launched pointing at the web server started by fossil ui listening on a private TCP port.

On all platforms, if the local or global settings web-browser is set, that is the command used to open an URL.

Otherwise, the specific actions vary by platform.

On Unix-like platforms other than Apple's, it looks for the first program from the list xdg-open, gnome-open, firefox, and google-chrome that it can find on the PATH.

On Apple platforms, it assumes that open is the command to open an URL in the user's configured default browser.

On Windows platforms, it assumes that start is the command to open an URL in the user's configured default browser.