godoc(1) extracts and generates documentation for Go programs


godoc [flag] command [ name ... ]


Godoc extracts and generates documentation for Go programs.

It has two modes.

Without the -http flag, it runs in command-line mode and prints plain text documentation to standard output and exits. If both a library package and a command with the same name exists, using the prefix cmd/ will force documentation on the command rather than the library package. If the -src flag is specified, godoc prints the exported interface of a package in Go source form, or the implementation of a specific exported language entity:

      godoc fmt                # documentation for package fmt
      godoc fmt Printf         # documentation for fmt.Printf
      godoc cmd/go             # force documentation for the go command
      godoc -src fmt           # fmt package interface in Go source form
      godoc -src fmt Printf    # implementation of fmt.Printf

In command-line mode, the -q flag enables search queries against a godoc running as a webserver. If no explicit server address is specified with the -server flag, godoc first tries localhost:6060 and then http://golang.org.

      godoc -q Reader
      godoc -q math.Sin
      godoc -server=:6060 -q sin

With the -http flag, it runs as a web server and presents the documentation as a web page.

      godoc -http=:6060

By default, godoc looks at the packages it finds via $GOROOT and $GOPATH (if set). Additional directories may be specified via the -path flag which accepts a list of colon-separated paths; unrooted paths are relative to the current working directory. Each path is considered as an additional root for packages in order of appearance. The last (absolute) path element is the prefix for the package path. For instance, given the flag value:


for a godoc started in /home/user/godoc, absolute paths are mapped to package paths as follows:

      /home/user/godoc/x -> godoc/x
      /home/bar/x        -> bar/x
      /public/x          -> public/x

When godoc runs as a web server and -index is set, a search index is maintained. The index is created at startup.

The index contains both identifier and full text search information (searchable via regular expressions). The maximum number of full text search results shown can be set with the -maxresults flag; if set to 0, no full text results are shown, and only an identifier index but no full text search index is created.

The presentation mode of web pages served by godoc can be controlled with the "m" URL parameter; it accepts a comma-separated list of flag names as value:

show documentation for all declarations, not just the exported ones
show all embedded methods, not just those of unexported anonymous fields
show the original source code rather then the extracted documentation
present the page in textual (command-line) form rather than HTML
present flat (not indented) directory listings using full paths

For instance, http://golang.org/pkg/math/big/?m=all,text shows the documentation for all (not just the exported) declarations of package big, in textual form (as it would appear when using godoc from the command line: "godoc -src math/big .*").

By default, godoc serves files from the file system of the underlying OS. Instead, a .zip file may be provided via the -zip flag, which contains the file system to serve. The file paths stored in the .zip file must use slash ('/') as path separator; and they must be unrooted. $GOROOT (or -goroot) must be set to the .zip file directory path containing the Go root directory. For instance, for a .zip file created by the command:

      zip go.zip $HOME/go

one may run godoc as follows:

      godoc -http=:6060 -zip=go.zip -goroot=$HOME/go

See "Godoc: documenting Go code" for how to write good comments for godoc: http://golang.org/doc/articles/godoc_documenting_go_code.html


verbose mode
arguments are considered search queries: a legal query is a single identifier (such as ToLower) or a qualified identifier (such as math.Sin).
print (exported) source in command-line mode
width of tabs in units of spaces
show timestamps with directory listings
enable identifier and full text search index (no search box is shown if -index is not set)
glob pattern specifying index files; if not empty, the index is read from these files in sorted order
index throttle value; a value of 0 means no time is allocated to the indexer (the indexer will never finish), a value of 1.0 means that index creation is running at full throttle (other goroutines may get no time while the index is built)
write index to a file; the file name must be specified with -index_files
maximum number of full text search results shown (no full text index is built if maxresults <= 0)
additional package directories (colon-separated)
print HTML in command-line mode
Go root directory
HTTP service address (e.g., '' or just ':6060')
webserver address for command line searches
directory containing alternate template files; if set, the directory may provide alternative template files for the files in $GOROOT/lib/godoc
print to standard output the data that would be served by an HTTP request for path
zip file providing the file system to serve; disabled if empty


This manual page was written by Michael Stapelberg <[email protected]>, for the Debian project (and may be used by others).