gofmt (1) - Linux Man Pages

gofmt: formats Go programs

NAME

gofmt - formats Go programs

SYNOPSIS

gofmt [flags] [ path ... ]

DESCRIPTION

Without an explicit path, it processes the standard input. Given a file, it operates on that file; given a directory, it operates on all .go files in that directory, recursively. (Files starting with a period are ignored.) By default, gofmt prints the reformatted sources to standard output.

OPTIONS

-d
Do not print reformatted sources to standard output. If a file's formatting is different than gofmt's, print diffs to standard output.
-e
Print all (including spurious) errors.
-l
Do not print reformatted sources to standard output. If a file's formatting is different from gofmt's, print its name to standard output.
-r rule
Apply the rewrite rule to the source before reformatting.
-s
Try to simplify code (after applying the rewrite rule, if any).
-w
Do not print reformatted sources to standard output. If a file's formatting is different from gofmt's, overwrite it with gofmt's version.

Formatting control flags:

-comments=true
Print comments; if false, all comments are elided from the output.
-tabs=true
Indent with tabs; if false, spaces are used instead.
-tabwidth=8
Tab width in spaces.

The rewrite rule specified with the -r flag must be a string of the form:

      pattern -> replacement

Both pattern and replacement must be valid Go expressions. In the pattern, single-character lowercase identifiers serve as wildcards matching arbitrary sub-expressions; those expressions will be substituted for the same identifiers in the replacement.

When gofmt reads from standard input, it accepts either a full Go program or a program fragment. A program fragment must be a syntactically valid declaration list, statement list, or expression. When formatting such a fragment, gofmt preserves leading indentation as well as leading and trailing spaces, so that individual sections of a Go program can be formatted by piping them through gofmt.

EXAMPLES

To check files for unnecessary parentheses:

      gofmt -r '(a) -> a' -l *.go

To remove the parentheses:

      gofmt -r '(a) -> a' -w *.go

To convert the package tree from explicit slice upper bounds to implicit ones:

      gofmt -r 'α[β:len(α)] -> α[β:]' -w $GOROOT/src/pkg

BUGS

The implementation of -r is a bit slow.

AUTHOR

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