A shell parser, formatter and interpreter. Supports POSIX Shell, Bash and
mksh. Requires Go 1.10 or later. A Go module is available via the module
branch.
go get -u mvdan.cc/sh/cmd/shfmt
shfmt formats shell programs. It can use tabs or any number of spaces to
indent. See canonical.sh for a quick look at its default
style.
You can feed it standard input, any number of files or any number of directories
to recurse into. When recursing, it will operate on .sh and .bash files and
ignore files starting with a period. It will also operate on files with no
extension and a shell shebang.
shfmt -l -w script.sh
Typically, CI builds should use the command below, to error if any shell scripts in a project don't adhere to the format:
shfmt -d .
Use -i N to indent with a number of spaces instead of tabs. There are other
formatting options - see shfmt -h. For example, to get the formatting
appropriate for Google's Style guide, use shfmt -i 2 -ci.
Packages are available for Arch, CRUX, Homebrew, NixOS and Void.
bash -n can be useful to check for syntax errors in shell scripts. However,
shfmt >/dev/null can do a better job as it checks for invalid UTF-8 and does
all parsing statically, including checking POSIX Shell validity:
$ echo '${foo:1 2}' | bash -n
$ echo '${foo:1 2}' | shfmt
1:9: not a valid arithmetic operator: 2
$ echo 'foo=(1 2)' | bash --posix -n
$ echo 'foo=(1 2)' | shfmt -p
1:5: arrays are a bash featurego get -u mvdan.cc/sh/cmd/gosh
Experimental shell that uses interp. Work in progress, so don't expect
stability just yet.
This project makes use of go-fuzz to find crashes and hangs in both the parser and the printer. To get started, run:
git checkout fuzz
./fuzz
- When indexing Bash associative arrays, always use quotes. The static parser will otherwise have to assume that the index is an arithmetic expression.
$ echo '${array[spaced string]}' | shfmt
1:16: not a valid arithmetic operator: string
$ echo '${array[dash-string]}' | shfmt
${array[dash - string]}$((and((ambiguity is not suported. Backtracking would complicate the parser and make streaming support viaio.Readerimpossible. The POSIX spec recommends to space the operands if$( (is meant.
$ echo '$((foo); (bar))' | shfmt
1:1: reached ) without matching $(( with ))- Some builtins like
exportandletare parsed as keywords. This is to allow statically parsing them and building their syntax tree, as opposed to just keeping the arguments as a slice of arguments.
A subset of the Go packages are available as an npm package called mvdan-sh. See the _js directory for more information.
- Docker images - by jamesmstone, PeterDaveHello
- format-shell - Atom plugin for
shfmt - micro - Editor with a built-in plugin for
shfmt - shell-format - VS Code plugin for
shfmt - vim-shfmt - Vim plugin for
shfmt