shellcheck/shellcheck.1.md

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% SHELLCHECK(1) Shell script analysis tool
# NAME
shellcheck - Shell script analysis tool
# SYNOPSIS
**shellcheck** [*OPTIONS*...] *FILES*...
# DESCRIPTION
ShellCheck is a static analysis and linting tool for sh/bash scripts. It's
mainly focused on handling typical beginner and intermediate level syntax
errors and pitfalls where the shell just gives a cryptic error message or
strange behavior, but it also reports on a few more advanced issues where
corner cases can cause delayed failures.
ShellCheck gives shell specific advice. Consider the line:
(( area = 3.14*r*r ))
+ For scripts starting with `#!/bin/sh` (or when using `-s sh`), ShellCheck
will warn that `(( .. ))` is not POSIX compliant (similar to checkbashisms).
+ For scripts starting with `#!/bin/bash` (or using `-s bash`), ShellCheck
will warn that decimals are not supported.
+ For scripts starting with `#!/bin/ksh` (or using `-s ksh`), ShellCheck will
not warn at all, as `ksh` supports decimals in arithmetic contexts.
# OPTIONS
**-e**\ *CODE1*[,*CODE2*...],\ **--exclude=***CODE1*[,*CODE2*...]
: Explicitly exclude the specified codes from the report. Subsequent **-e**
options are cumulative, but all the codes can be specified at once,
comma-separated as a single argument.
**-f** *FORMAT*, **--format=***FORMAT*
: Specify the output format of shellcheck, which prints its results in the
standard output. Subsequent **-f** options are ignored, see **FORMATS**
below for more information.
**-s**\ *shell*,\ **--shell=***shell*
: Specify Bourne shell dialect. Valid values are *sh*, *bash* and *ksh*.
The default is to use the file's shebang, or *bash* if the target shell
can't be determined.
**-V**\ *version*,\ **--version**
: Print version and exit.
# FORMATS
**tty**
: Plain text, human readable output. This is the default.
**gcc**
: GCC compatible output. Useful for editors that support compiling and
showing syntax errors.
For example, in Vim, `:set makeprg=shellcheck\ -f\ gcc\ %` will allow
using `:make` to check the script, and `:cnext` to jump to the next error.
<file>:<line>:<column>: <type>: <message>
**checkstyle**
: Checkstyle compatible XML output. Supported directly or through plugins
by many IDEs and build monitoring systems.
<?xml version='1.0' encoding='UTF-8'?>
<checkstyle version='4.3'>
<file name='file'>
<error
line='line'
column='column'
severity='severity'
message='message'
source='ShellCheck.SC####' />
...
</file>
...
</checkstyle>
**json**
: Json is a popular serialization format that is more suitable for web
applications. ShellCheck's json is compact and contains only the bare
minimum.
[
{
"file": "filename",
"line": lineNumber,
"column": columnNumber,
"level": "severitylevel",
"code": errorCode,
"message": "warning message"
},
...
]
# DIRECTIVES
ShellCheck directives can be specified as comments in the shell script
before a command or block:
# shellcheck key=value key=value
command-or-structure
For example, to suppress SC2035 about using `./*.jpg`:
# shellcheck disable=SC2035
echo "Files: " *.jpg
Here a shell brace group is used to suppress on multiple lines:
# shellcheck disable=SC2016
{
echo 'Modifying $PATH'
echo 'PATH=foo:$PATH' >> ~/.bashrc
}
Valid keys are:
**disable**
: Disables a comma separated list of error codes for the following command.
The command can be a simple command like `echo foo`, or a compound command
like a function definition, subshell block or loop.
# AUTHOR
ShellCheck is written and maintained by Vidar Holen.
# REPORTING BUGS
Bugs and issues can be reported on GitHub:
https://github.com/koalaman/shellcheck/issues
# COPYRIGHT
Copyright 2012-2015, Vidar Holen.
Licensed under the GNU General Public License version 3 or later,
see http://gnu.org/licenses/gpl.html
# SEE ALSO
sh(1) bash(1)