shfmt(1)
shfmt - Format shell programs
shfmt [flags] [path...]
shfmt formats shell programs. If the only argument is a dash (-) or no arguments are given, standard input will be used. If a given path is a directory, all shell scripts found under that directory will be used.
If any EditorConfig files are found, they will be used to apply formatting options. If any parser or printer flags are given to the tool, no EditorConfig formatting options will be used. A default like -i=0 can be used for this purpose.
shfmt's default shell formatting was chosen to be consistent, common, and predictable. Some aspects of the format can be configured via printer flags.
--version Show version and exit.
-l, --list List files whose formatting differs from shfmt's.
-w, --write Write result to file instead of stdout.
-d, --diff Error with a diff when the formatting differs.
The diff uses color when the output is a terminal.
To never use color, set a non-empty *NO_COLOR* or *TERM=dumb*.
To always use color, set a non-empty *FORCE_COLOR*.-s, --simplify Simplify the code.
-mn, --minify Minify the code to reduce its size (implies -s).
--apply-ignore Always apply EditorConfig ignore rules.
When formatting files directly, ignore rules are skipped without this flag.
Should be useful to any tools or editors which format stdin or a single file.
When printing results to stdout, an ignored file results in no output at all.--filename str Provide a name for the standard input file.
Use of this flag is necessary for EditorConfig support to work with stdin,
since EditorConfig files are found relative to the location of a script.-ln, --language-dialect Language dialect (bash/posix/mksh/bats, default auto).
When set to *auto*, the language is detected from the input filename,
as long as it has a shell extension like *foo.mksh*. Otherwise, if the input
begins with a shell shebang like *#!/bin/sh*, that's used instead.
If neither come up with a result, *bash* is used as a fallback.
The filename extension *.sh* is a special case: it implies *posix*,
but may be overridden by a valid shell shebang.-p, --posix Shorthand for -ln=posix.
-i, --indent Indent: 0 for tabs (default), >0 for number of spaces.
-bn, --binary-next-line Binary ops like && and | may start a line.
-ci, --case-indent Switch cases will be indented.
-sr, --space-redirects Redirect operators will be followed by a space.
-kp, --keep-padding Keep column alignment paddings.
This flag is *DEPRECATED* and will be removed in the next major version.
For more information, see: https://github.com/mvdan/sh/issues/658-fn, --func-next-line Function opening braces are placed on a separate line.
-f, --find Recursively find all shell files and print the paths.
--to-json Print syntax tree to stdout as a typed JSON.
--from-json Read syntax tree from stdin as a typed JSON.
Format all the scripts under the current directory, printing which are modified:
shfmt -l -w .For CI, one can use a variant where formatting changes are just shown as diffs:
shfmt -d .The following formatting flags closely resemble Google's shell style defined in https://google.github.io/styleguide/shellguide.html:
shfmt -i 2 -ci -bnBelow is a sample EditorConfig file as defined by https://editorconfig.org/, showing how to set any option:
[*.sh]
# like -i=4
indent_style = space
indent_size = 4
# --language-variant
shell_variant = posix
binary_next_line = true
# --case-indent
switch_case_indent = true
space_redirects = true
keep_padding = true
# --func-next-line
function_next_line = true
# Ignore the entire "third_party" directory when calling shfmt on directories,
# such as "shfmt -l -w .". When formatting files directly,
# like "shfmt -w third_party/foo.sh" or "shfmt --filename=third_party/foo.sh",
# the ignore logic is applied only when the --apply-ignore flag is given.
[third_party/**]
ignore = trueEditorConfig sections may also use [[shell]] or [[bash]] to match any shell or bash scripts,
which is particularly useful when scripts use a shebang but no extension.
Note that this feature is outside of the EditorConfig spec and may be changed in the future.
shfmt can also replace bash -n to check shell scripts for syntax errors. It is more exhaustive, as it parses all syntax statically and requires valid UTF-8:
$ echo '${foo:1 2}' | bash -n
$ echo '${foo:1 2}' | shfmt >/dev/null
1:9: not a valid arithmetic operator: 2
$ echo 'foo=(1 2)' | bash --posix -n
$ echo 'foo=(1 2)' | shfmt -p >/dev/null
1:5: arrays are a bash featureMaintained by Daniel Martí mvdan@mvdan.cc, who is assisted by other open source contributors. For more information and development, see https://github.com/mvdan/sh.