1SHELLCHECK(1) SHELLCHECK(1)
2
6 shellcheck - Shell script analysis tool
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9 shellcheck [OPTIONS...] FILES...
10
12 ShellCheck is a static analysis and linting tool for sh/bash scripts.
13 It's mainly focused on handling typical beginner and intermediate level
14 syntax errors and pitfalls where the shell just gives a cryptic error
15 message or strange behavior, but it also reports on a few more advanced
16 issues where corner cases can cause delayed failures.
17 ShellCheck gives shell specific advice. Consider this line:
19 (( area = 3.14*r*r ))
21 · For scripts starting with #!/bin/sh (or when using -s sh), ShellCheck
23 will warn that (( .. )) is not POSIX compliant (similar to check‐
24 bashisms).
25 · For scripts starting with #!/bin/bash (or using -s bash), ShellCheck
27 will warn that decimals are not supported.
28 · For scripts starting with #!/bin/ksh (or using -s ksh), ShellCheck
30 will not warn at all, as ksh supports decimals in arithmetic con‐
31 texts.
32
34 -a, --check-sourced
35 Emit warnings in sourced files. Normally, shellcheck will only
36 warn about issues in the specified files. With this option, any
37 issues in sourced files will also be reported.
38 -C[WHEN], --color[=WHEN]
40 For TTY output, enable colors always, never or auto. The de‐
41 fault is auto. --color without an argument is equivalent to
42 --color=always.
43 -i CODE1[,CODE2...], --include=CODE1[,CODE2...]
45 Explicitly include only the specified codes in the report. Sub‐
46 sequent -i options are cumulative, but all the codes can be
47 specified at once, comma-separated as a single argument. In‐
48 clude options override any provided exclude options.
49 -e CODE1[,CODE2...], --exclude=CODE1[,CODE2...]
51 Explicitly exclude the specified codes from the report. Subse‐
52 quent -e options are cumulative, but all the codes can be speci‐
53 fied at once, comma-separated as a single argument.
54 -f FORMAT, --format=FORMAT
56 Specify the output format of shellcheck, which prints its re‐
57 sults in the standard output. Subsequent -f options are ig‐
58 nored, see FORMATS below for more information.
59 --list-optional
61 Output a list of known optional checks. These can be enabled
62 with -o flags or enable directives.
63 --norc Don't try to look for .shellcheckrc configuration files.
65 -o NAME1[,NAME2...], --enable=NAME1[,NAME2...]
67 Enable optional checks. The special name all enables all of
68 them. Subsequent -o options accumulate. This is equivalent to
69 specifying enable directives.
70 -P SOURCEPATH, --source-path=SOURCEPATH
72 Specify paths to search for sourced files, separated by : on
73 Unix and ; on Windows. This is equivalent to specifying search-
74 path directives.
75 -s shell, --shell=shell
77 Specify Bourne shell dialect. Valid values are sh, bash, dash
78 and ksh. The default is to deduce the shell from the file's
79 shell directive, shebang, or .bash/.bats/.dash/.ksh extension,
80 in that order. sh refers to POSIX sh (not the system's), and
81 will warn of portability issues.
82 -S SEVERITY, --severity=severity
84 Specify minimum severity of errors to consider. Valid values in
85 order of severity are error, warning, info and style. The de‐
86 fault is style.
87 -V, --version
89 Print version information and exit.
90 -W NUM, --wiki-link-count=NUM
92 For TTY output, show NUM wiki links to more information about
93 mentioned warnings. Set to 0 to disable them entirely.
94 -x, --external-sources
96 Follow source statements even when the file is not specified as
97 input. By default, shellcheck will only follow files specified
98 on the command line (plus /dev/null). This option allows fol‐
99 lowing any file the script may source.
100 FILES...
102 One or more script files to check, or "-" for standard input.
103
105 tty Plain text, human readable output. This is the default.
106 gcc GCC compatible output. Useful for editors that support compil‐
108 ing and showing syntax errors.
109 For example, in Vim, :set makeprg=shellcheck\ -f\ gcc\ % will
111 allow using :make to check the script, and :cnext to jump to the
112 next error.
113 <file>:<line>:<column>: <type>: <message>
115 checkstyle
117 Checkstyle compatible XML output. Supported directly or through
118 plugins by many IDEs and build monitoring systems.
119 <?xml version='1.0' encoding='UTF-8'?>
121 <checkstyle version='4.3'>
122 <file name='file'>
123 <error
124 line='line'
125 column='column'
126 severity='severity'
127 message='message'
128 source='ShellCheck.SC####' />
129 ...
130 </file>
131 ...
132 </checkstyle>
133 diff Auto-fixes in unified diff format. Can be piped to git apply or
135 patch -p1 to automatically apply fixes.
136 --- a/test.sh
138 +++ b/test.sh
139 @@ -2,6 +2,6 @@
140 ## Example of a broken script.
141 for f in $(ls *.m3u)
142 do
143 - grep -qi hq.*mp3 $f \
144 + grep -qi hq.*mp3 "$f" \
145 && echo -e 'Playlist $f contains a HQ file in mp3 format'
146 done
147 json1 Json is a popular serialization format that is more suitable for
149 web applications. ShellCheck's json is compact and contains on‐
150 ly the bare minimum. Tabs are counted as 1 character.
151 {
153 comments: [
154 {
155 "file": "filename",
156 "line": lineNumber,
157 "column": columnNumber,
158 "level": "severitylevel",
159 "code": errorCode,
160 "message": "warning message"
161 },
162 ...
163 ]
164 }
165 json This is a legacy version of the json1 format. It's a raw array
167 of comments, and all offsets have a tab stop of 8.
168 quiet Suppress all normal output. Exit with zero if no issues are
170 found, otherwise exit with one. Stops processing after the
171 first issue.
172
174 ShellCheck directives can be specified as comments in the shell script.
175 If they appear before the first command, they are considered file-wide.
176 Otherwise, they apply to the immediately following command or block:
177 # shellcheck key=value key=value
179 command-or-structure
180 For example, to suppress SC2035 about using ./*.jpg:
182 # shellcheck disable=SC2035
184 echo "Files: " *.jpg
185 To tell ShellCheck where to look for an otherwise dynamically deter‐
187 mined file:
188 # shellcheck source=./lib.sh
190 source "$(find_install_dir)/lib.sh"
191 Here a shell brace group is used to suppress a warning on multiple
193 lines:
194 # shellcheck disable=SC2016
196 {
197 echo 'Modifying $PATH'
198 echo 'PATH=foo:$PATH' >> ~/.bashrc
199 }
200 Valid keys are:
202 disable
204 Disables a comma separated list of error codes for the following
205 command. The command can be a simple command like echo foo, or
206 a compound command like a function definition, subshell block or
207 loop.
208 enable Enable an optional check by name, as listed with --list-option‐
210 al. Only file-wide enable directives are considered.
211 source Overrides the filename included by a source/. statement. This
213 can be used to tell shellcheck where to look for a file whose
214 name is determined at runtime, or to skip a source by telling it
215 to use /dev/null.
216 source-path
218 Add a directory to the search path for source/. statements (by
219 default, only ShellCheck's working directory is included). Ab‐
220 solute paths will also be rooted in these paths. The special
221 path SCRIPTDIR can be used to specify the currently checked
222 script's directory, as in source-path=SCRIPTDIR or source-
223 path=SCRIPTDIR/../libs. Multiple paths accumulate, and -P takes
224 precedence over them.
225 shell Overrides the shell detected from the shebang. This is useful
227 for files meant to be included (and thus lacking a shebang), or
228 possibly as a more targeted alternative to 'disable=2039'.
229
231 Unless --norc is used, ShellCheck will look for a file .shellcheckrc or
232 shellcheckrc in the script's directory and each parent directory. If
233 found, it will read key=value pairs from it and treat them as file-wide
234 directives.
235 Here is an example .shellcheckrc:
237 # Look for 'source'd files relative to the checked script,
239 # and also look for absolute paths in /mnt/chroot
240 source-path=SCRIPTDIR
241 source-path=/mnt/chroot
242 # Turn on warnings for unquoted variables with safe values
244 enable=quote-safe-variables
245 # Turn on warnings for unassigned uppercase variables
247 enable=check-unassigned-uppercase
248 # Allow [ ! -z foo ] instead of suggesting -n
250 disable=SC2236
251 If no .shellcheckrc is found in any of the parent directories,
253 ShellCheck will look in ~/.shellcheckrc followed by the XDG config di‐
254 rectory (usually ~/.config/shellcheckrc) on Unix, or %APPDA‐
255 TA%/shellcheckrc on Windows. Only the first file found will be used.
256 Note for Snap users: the Snap sandbox disallows access to hidden files.
258 Use shellcheckrc without the dot instead.
259 Note for Docker users: ShellCheck will only be able to look for files
261 that are mounted in the container, so ~/.shellcheckrc will not be read.
262
264 The environment variable SHELLCHECK_OPTS can be set with default flags:
265 export SHELLCHECK_OPTS='--shell=bash --exclude=SC2016'
267 Its value will be split on spaces and prepended to the command line on
269 each invocation.
270
272 ShellCheck uses the following exit codes:
273 · 0: All files successfully scanned with no issues.
275 · 1: All files successfully scanned with some issues.
277 · 2: Some files could not be processed (e.g. file not found).
279 · 3: ShellCheck was invoked with bad syntax (e.g. unknown flag).
281 · 4: ShellCheck was invoked with bad options (e.g. unknown formatter).
283
285 This version of ShellCheck is only available in English. All files are
286 leniently decoded as UTF-8, with a fallback of ISO-8859-1 for invalid
287 sequences. LC_CTYPE is respected for output, and defaults to UTF-8 for
288 locales where encoding is unspecified (such as the C locale).
289 Windows users seeing commitBuffer: invalid argument (invalid character)
291 should set their terminal to use UTF-8 with chcp 65001.
292
294 ShellCheck is developed and maintained by Vidar Holen, with assistance
295 from a long list of wonderful contributors.
296
298 Bugs and issues can be reported on GitHub:
299 https://github.com/koalaman/shellcheck/issues
301
303 Copyright 2012-2019, Vidar Holen and contributors. Licensed under the
304 GNU General Public License version 3 or later, see https://gnu.org/li‐
305 censes/gpl.html
306
308 sh(1) bash(1)
309Shell script analysis tool SHELLCHECK(1)