<a href="https://gitpod.io/#https://github.com/alibaba/java-dns-cache-manipulator"><img src="https://img.shields.io/badge/Gitpod-ready to code-339933?label=gitpod&logo=gitpod&logoColor=white" alt="gitpod: Ready to Code"></a>

Close

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

<a href="https://search.maven.org/artifact/com.alibaba/dns-cache-manipulator"><img src="https://img.shields.io/maven-central/v/com.alibaba/dns-cache-manipulator?color=2d545e&logo=apache-maven&logoColor=white" alt="Maven Central"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

<a href="https://search.maven.org/artifact/com.alibaba/dns-cache-manipulator"><img src="https://img.shields.io/maven-central/v/com.alibaba/dns-cache-manipulator?color=2d545e&logo=apache-maven&logoColor=white" alt="Maven Central"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

     export JAVA_HOME=`/usr/libexec/java_home`

Close

Use $(STATEMENT) instead of legacy `STATEMENT`

Problematic code

echo "Current time: `date`"

Correct code

echo "Current time: $(date)"

Rationale

Backtick command substitution `STATEMENT` is legacy syntax with several issues.

1. It has a series of undefined behaviors related to quoting in POSIX.
2. It imposes a custom escaping mode with surprising results.
3. It's exceptionally hard to nest.

$(STATEMENT) command substitution has none of these problems, and is therefore strongly encouraged.

Exceptions

None.

See also

• http://mywiki.wooledge.org/BashFAQ/082

Notice

Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.

<a href="https://github.com/alibaba/java-dns-cache-manipulator/network/dependents"><img src="https://badgen.net/github/dependents-repo/alibaba/java-dns-cache-manipulator?label=user%20repos" alt="user repos"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

Close

MD012 - Multiple consecutive blank lines

Tags: whitespace, blank_lines

Aliases: no-multiple-blanks

This rule is triggered when there are multiple consecutive blank lines in the document:

Some text here


Some more text here

To fix this, delete the offending lines:

Some text here

Some more text here

Note: this rule will not be triggered if there are multiple consecutive blank lines inside code blocks.

<a href="https://github.com/alibaba/java-dns-cache-manipulator/releases"><img src="https://img.shields.io/github/release/alibaba/java-dns-cache-manipulator.svg" alt="GitHub release"></a>

Close

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

<a href="https://openjdk.java.net/"><img src="https://img.shields.io/badge/Java-8+-339933?logo=openjdk&logoColor=white" alt="Java support"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

<a href="https://github.com/alibaba/java-dns-cache-manipulator/stargazers"><img src="https://img.shields.io/github/stars/alibaba/java-dns-cache-manipulator?style=flat" alt="GitHub Stars"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

<a href="https://github.com/alibaba/java-dns-cache-manipulator/network/dependents"><img src="https://badgen.net/github/dependents-repo/alibaba/java-dns-cache-manipulator?label=user%20repos" alt="user repos"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

<a href="https://gitpod.io/#https://github.com/alibaba/java-dns-cache-manipulator"><img src="https://img.shields.io/badge/Gitpod-ready to code-339933?label=gitpod&logo=gitpod&logoColor=white" alt="gitpod: Ready to Code"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`

Close

Use $(STATEMENT) instead of legacy `STATEMENT`

Problematic code

echo "Current time: `date`"

Correct code

echo "Current time: $(date)"

Rationale

Backtick command substitution `STATEMENT` is legacy syntax with several issues.

1. It has a series of undefined behaviors related to quoting in POSIX.
2. It imposes a custom escaping mode with surprising results.
3. It's exceptionally hard to nest.

$(STATEMENT) command substitution has none of these problems, and is therefore strongly encouraged.

Exceptions

None.

See also

• http://mywiki.wooledge.org/BashFAQ/082

Notice

Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.

        javaHome="`dirname \"$javaExecutable\"`"

Close

Use $(STATEMENT) instead of legacy `STATEMENT`

Problematic code

echo "Current time: `date`"

Correct code

echo "Current time: $(date)"

Rationale

Backtick command substitution `STATEMENT` is legacy syntax with several issues.

1. It has a series of undefined behaviors related to quoting in POSIX.
2. It imposes a custom escaping mode with surprising results.
3. It's exceptionally hard to nest.

$(STATEMENT) command substitution has none of these problems, and is therefore strongly encouraged.

Exceptions

None.

See also

• http://mywiki.wooledge.org/BashFAQ/082

Notice

Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.

  local basedir=$(pwd)

Close

Declare and assign separately to avoid masking return values.

Problematic code:

export foo="$(mycmd)"

Correct code:

foo=$(mycmd)
export foo

Rationale:

In the original code, the return value of mycmd is ignored, and export will instead always return true. This may prevent conditionals, set -e and traps from working correctly.

When first marked for export and assigned separately, the return value of the assignment will be that of mycmd. This avoids the problem.

Exceptions:

If you intend to ignore the return value of an assignment, you can either ignore this warning or use

foo=$(mycmd) || true
export foo

Shellcheck does not warn about export foo=bar because bar is a literal and not a command substitution with an independent return value. It also does not warn about local -r foo=$(cmd), where declaration and assignment must be in the same command.

Notice

Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.

"$JAVACMD" -Xmx128m $DCM_OPTS -classpath $CLASSPATH com.alibaba.dcm.tool.DcmTool "$@"

Close

Double quote to prevent globbing and word splitting.

Problematic code:

echo $1
for i in $*; do :; done # this done and the next one also applies to expanding arrays.
for i in $@; do :; done

Correct code:

echo "$1"
for i in "$@"; do :; done # or, 'for i; do'

Rationale

The first code looks like "print the first argument". It's actually "Split the first argument by IFS (spaces, tabs and line feeds). Expand each of them as if it was a glob. Join all the resulting strings and filenames with spaces. Print the result."

The second one looks like "iterate through all arguments". It's actually "join all the arguments by the first character of IFS (space), split them by IFS and expand each of them as globs, and iterate on the resulting list". The third one skips the joining part.

Quoting variables prevents word splitting and glob expansion, and prevents the script from breaking when input contains spaces, line feeds, glob characters and such.

Strictly speaking, only expansions themselves need to be quoted, but for stylistic reasons, entire arguments with multiple variable and literal parts are often quoted as one:

$HOME/$dir/dist/bin/$file        # Unquoted (bad)
"$HOME"/"$dir"/dist/bin/"$file"  # Minimal quoting (good)
"$HOME/$dir/dist/bin/$file"      # Canonical quoting (good)

When quoting composite arguments, make sure to exclude globs and brace expansions, which lose their special meaning in double quotes: "$HOME/$dir/src/*.c" will not expand, but "$HOME/$dir/src"/*.c will.

Note that $( ) starts a new context, and variables in it have to be quoted independently:

echo "This $variable is quoted $(but this $variable is not)"
echo "This $variable is quoted $(and now this "$variable" is too)"

Exceptions

Sometimes you want to split on spaces, like when building a command line:

options="-j 5 -B"
make $options file

Just quoting this doesn't work. Instead, you should have used an array (bash, ksh, zsh):

options=(-j 5 -B) # ksh: set -A options -- -j 5 -B
make "${options[@]}" file

or a function (POSIX):

make_with_flags() { make -j 5 -B "$@"; }
make_with_flags file

To split on spaces but not perform glob expansion, Posix has a set -f to disable globbing. You can disable word splitting by setting IFS=''.

Similarly, you might want an optional argument:

debug=""
[[ $1 == "--trace-commands" ]] && debug="-x"
bash $debug script

Quoting this doesn't work, since in the default case, "$debug" would expand to one empty argument while $debug would expand into zero arguments. In this case, you can use an array with zero or one elements as outlined above, or you can use an unquoted expansion with an alternate value:

debug=""
[[ $1 == "--trace-commands" ]] && debug="yes"
bash ${debug:+"-x"} script

This is better than an unquoted value because the alternative value can be properly quoted, e.g. wget ${output:+ -o "$output"}.

---

As always, this warning can be [[ignore]]d on a case-by-case basis.

this is especially relevant when BASH many not be available for the array work around. For example, use in eval or in command options where script has total control of the variables...

FLAGS="-av -e 'ssh -x' --delete --delete-excluded"
...
# shellcheck disable=SC2086
eval rsync $FLAGS ~/dir remote_host:dir

Notice

Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.

<a href="https://github.com/alibaba/java-dns-cache-manipulator/fork"><img src="https://img.shields.io/github/forks/alibaba/java-dns-cache-manipulator?style=flat" alt="GitHub Forks"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

<a href="https://alibaba.github.io/java-dns-cache-manipulator/apidocs/"><img src="https://img.shields.io/github/release/alibaba/java-dns-cache-manipulator?label=javadoc&color=339933&logo=read-the-docs&logoColor=white" alt="Javadocs"></a>

Close

MD013 - Line length

Tags: line_length

Aliases: line-length Parameters: linelength, codeblocks, tables (number; default 80, boolean; default true)

This rule is triggered when there are lines that are longer than the configured line length (default: 80 characters). To fix this, split the line up into multiple lines.

This rule has an exception where there is no whitespace beyond the configured line length. This allows you to still include items such as long URLs without being forced to break them in the middle.

You also have the option to exclude this rule for code blocks and tables. To do this, set the code_blocks and/or tables parameters to false.

Code blocks are included in this rule by default since it is often a requirement for document readability, and tentatively compatible with code rules. Still, some languages do not lend themselves to short lines.

<a href="https://github.com/alibaba/java-dns-cache-manipulator/releases"><img src="https://img.shields.io/github/release/alibaba/java-dns-cache-manipulator.svg" alt="GitHub release"></a>

Close

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

        return null == host || "0.0.0.0".equals(host);

Close

AvoidUsingHardCodedIP

Since: PMD 4.1

Priority: Medium

Categories: Style

Remediation Points: 50000

Application with hard-coded IP addresses can become impossible to deploy in some cases. Externalizing IP adresses is preferable.

Example:

public class Foo {
 private String ip = '127.0.0.1'; // not recommended
}

  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then

Close

Use $(STATEMENT) instead of legacy `STATEMENT`

Problematic code

echo "Current time: `date`"

Correct code

echo "Current time: $(date)"

Rationale

Backtick command substitution `STATEMENT` is legacy syntax with several issues.

1. It has a series of undefined behaviors related to quoting in POSIX.
2. It imposes a custom escaping mode with surprising results.
3. It's exceptionally hard to nest.

$(STATEMENT) command substitution has none of these problems, and is therefore strongly encouraged.

Exceptions

None.

See also

• http://mywiki.wooledge.org/BashFAQ/082

Notice

Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.