.TH "SHELLCHECK" "1" "" "Shell script analysis tool" "" .SH NAME .PP shellcheck \- Shell script analysis tool .SH SYNOPSIS .PP \f[B]shellcheck\f[] [\f[I]OPTIONS\f[]...] \f[I]FILES\f[]... .SH DESCRIPTION .PP ShellCheck is a static analysis and linting tool for sh/bash scripts. It\[aq]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. .PP ShellCheck gives shell specific advice. Consider this line: .IP .nf \f[C] ((\ area\ =\ 3.14*r*r\ )) \f[] .fi .IP \[bu] 2 For scripts starting with \f[C]#!/bin/sh\f[] (or when using \f[C]\-s\ sh\f[]), ShellCheck will warn that \f[C]((\ ..\ ))\f[] is not POSIX compliant (similar to checkbashisms). .IP \[bu] 2 For scripts starting with \f[C]#!/bin/bash\f[] (or using \f[C]\-s\ bash\f[]), ShellCheck will warn that decimals are not supported. .IP \[bu] 2 For scripts starting with \f[C]#!/bin/ksh\f[] (or using \f[C]\-s\ ksh\f[]), ShellCheck will not warn at all, as \f[C]ksh\f[] supports decimals in arithmetic contexts. .SH OPTIONS .TP .B \f[B]\-C\f[][\f[I]WHEN\f[]],\ \f[B]\-\-color\f[][=\f[I]WHEN\f[]] For TTY output, enable colors \f[I]always\f[], \f[I]never\f[] or \f[I]auto\f[]. The default is \f[I]auto\f[]. \f[B]\-\-color\f[] without an argument is equivalent to \f[B]\-\-color=always\f[]. .RS .RE .TP .B \f[B]\-e\f[]\ \f[I]CODE1\f[][,\f[I]CODE2\f[]...],\ \f[B]\-\-exclude=\f[]\f[I]CODE1\f[][,\f[I]CODE2\f[]...] Explicitly exclude the specified codes from the report. Subsequent \f[B]\-e\f[] options are cumulative, but all the codes can be specified at once, comma\-separated as a single argument. .RS .RE .TP .B \f[B]\-f\f[] \f[I]FORMAT\f[], \f[B]\-\-format=\f[]\f[I]FORMAT\f[] Specify the output format of shellcheck, which prints its results in the standard output. Subsequent \f[B]\-f\f[] options are ignored, see \f[B]FORMATS\f[] below for more information. .RS .RE .TP .B \f[B]\-s\f[]\ \f[I]shell\f[],\ \f[B]\-\-shell=\f[]\f[I]shell\f[] Specify Bourne shell dialect. Valid values are \f[I]sh\f[], \f[I]bash\f[], \f[I]dash\f[] and \f[I]ksh\f[]. The default is to use the file\[aq]s shebang, or \f[I]bash\f[] if the target shell can\[aq]t be determined. .RS .RE .TP .B \f[B]\-V\f[],\ \f[B]\-\-version\f[] Print version information and exit. .RS .RE .TP .B \f[B]\-x\f[],\ \f[B]\-\-external\-sources\f[] Follow \[aq]source\[aq] statements even when the file is not specified as input. By default, \f[C]shellcheck\f[] will only follow files specified on the command line (plus \f[C]/dev/null\f[]). This option allows following any file the script may \f[C]source\f[]. .RS .RE .SH FORMATS .TP .B \f[B]tty\f[] Plain text, human readable output. This is the default. .RS .RE .TP .B \f[B]gcc\f[] GCC compatible output. Useful for editors that support compiling and showing syntax errors. .RS .PP For example, in Vim, \f[C]:set\ makeprg=shellcheck\\\ \-f\\\ gcc\\\ %\f[] will allow using \f[C]:make\f[] to check the script, and \f[C]:cnext\f[] to jump to the next error. .IP .nf \f[C] :::\ :\ \f[] .fi .RE .TP .B \f[B]checkstyle\f[] Checkstyle compatible XML output. Supported directly or through plugins by many IDEs and build monitoring systems. .RS .IP .nf \f[C] \ \ \ \ \ \ \ \ \ \ ... \ \ \ \ ... \f[] .fi .RE .TP .B \f[B]json\f[] Json is a popular serialization format that is more suitable for web applications. ShellCheck\[aq]s json is compact and contains only the bare minimum. .RS .IP .nf \f[C] [ \ \ { \ \ \ \ "file":\ "filename", \ \ \ \ "line":\ lineNumber, \ \ \ \ "column":\ columnNumber, \ \ \ \ "level":\ "severitylevel", \ \ \ \ "code":\ errorCode, \ \ \ \ "message":\ "warning\ message" \ \ }, \ \ ... ] \f[] .fi .RE .SH DIRECTIVES .PP ShellCheck directives can be specified as comments in the shell script before a command or block: .IP .nf \f[C] #\ shellcheck\ key=value\ key=value command\-or\-structure \f[] .fi .PP For example, to suppress SC2035 about using \f[C]\&./*.jpg\f[]: .IP .nf \f[C] #\ shellcheck\ disable=SC2035 echo\ "Files:\ "\ *.jpg \f[] .fi .PP To tell ShellCheck where to look for an otherwise dynamically determined file: .IP .nf \f[C] #\ shellcheck\ source=./lib.sh source\ "$(find_install_dir)/lib.sh" \f[] .fi .PP Here a shell brace group is used to suppress a warning on multiple lines: .IP .nf \f[C] #\ shellcheck\ disable=SC2016 { \ \ echo\ \[aq]Modifying\ $PATH\[aq] \ \ echo\ \[aq]PATH=foo:$PATH\[aq]\ >>\ ~/.bashrc } \f[] .fi .PP Valid keys are: .TP .B \f[B]disable\f[] Disables a comma separated list of error codes for the following command. The command can be a simple command like \f[C]echo\ foo\f[], or a compound command like a function definition, subshell block or loop. .RS .RE .TP .B \f[B]source\f[] Overrides the filename included by a \f[C]source\f[]/\f[C]\&.\f[] statement. This can be used to tell shellcheck where to look for a file whose name is determined at runtime, or to skip a source by telling it to use \f[C]/dev/null\f[]. .RS .RE .SH ENVIRONMENT VARIABLES .PP The environment variable \f[C]SHELLCHECK_OPTS\f[] can be set with default flags: .IP .nf \f[C] export\ SHELLCHECK_OPTS=\[aq]\-\-shell=bash\ \-\-exclude=SC2016\[aq] \f[] .fi .PP Its value will be split on spaces and prepended to the command line on each invocation. .SH RETURN VALUES .PP ShellCheck uses the follow exit codes: .IP \[bu] 2 0: All files successfully scanned with no issues. .IP \[bu] 2 1: All files successfully scanned with some issues. .IP \[bu] 2 2: Some files could not be processed (e.g. file not found). .IP \[bu] 2 3: ShellCheck was invoked with bad syntax (e.g. unknown flag). .IP \[bu] 2 4: ShellCheck was invoked with bad options (e.g. unknown formatter). .SH AUTHOR .PP ShellCheck is written and maintained by Vidar Holen. .SH REPORTING BUGS .PP Bugs and issues can be reported on GitHub: .PP https://github.com/koalaman/shellcheck/issues .SH COPYRIGHT .PP Copyright 2012\-2015, Vidar Holen. Licensed under the GNU General Public License version 3 or later, see http://gnu.org/licenses/gpl.html .SH SEE ALSO .PP sh(1) bash(1)