GOFMT(1) General Commands Manual GOFMT(1)
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 out-
put.
-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 match-
ing 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 'a[B:len(a)] -> a[B:]' -w $GOROOT/src/pkg
BUGS
The implementation of -r is a bit slow.
AUTHOR
This manual page was written by Michael Stapelberg <stapelberg@debian.org>, for the Debian project (and may be used by others).
2012-05-13 GOFMT(1)
