2 SC2217

Joachim Ansorg edited this page 2021-11-12 19:51:09 +01:00

Table of Contents

• Redirecting to echo, a command that doesn't read stdin. Bad quoting or missing xargs?
• Problematic code:
• Correct code:
• Rationale:
• Exceptions:

Redirecting to echo, a command that doesn't read stdin. Bad quoting or missing xargs?

Problematic code:

echo << eof
  Hello World
eof

Correct code:

cat << eof
  Hello World
eof

Rationale:

You are redirecting to one of several commands that don't read from stdin.

This may happen when:

• Confusing one command for another, e.g. using echo where cat was intended.
• Incorrectly quoting angle brackets, e.g. using echo <p>Hello which tries to read from a file p.
• Missing xargs, e.g. mv -t dir < files instead of xargs mv -t dir < files (or more safely, tr '\n' '\0' < files | xargs -0 mv -t dir), because stdin should be passed as parameters.

Check your logic, and rewrite the command so data is passed correctly.

Exceptions:

If you've overridden a command to return output, you can either rename it to make this obvious, or ignore this message.

ShellCheck

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