5

SC2209

Joachim Ansorg edited this page 2021-11-12 19:50:04 +01:00

Table of Contents

• Use var=$(command) to assign output (or quote to assign string).
• Problematic code:
• Correct code:
• Rationale:
• Exceptions:
• Related resources:

Use var=$(command) to assign output (or quote to assign string).

Problematic code:

user=whoami         # Want to run whoami and assign output

PAGER=cat git log   # Want to assign the string "cat"

Correct code:

user=$(whoami)

PAGER="cat" git log

Rationale:

Putting var= in front of a command will not assign its output. Use var=$(my command here) to execute the command and capture its output.

If you do want to assign a literal string, use quotes to make this clear to shellcheck and humans alike.

Exceptions:

None.

Quoting a single command (as in PAGER="cat" above) doesn't change how the script works. It's purely to show shellcheck (and humans) that a literal assignment of a command name is intentional.

This warning triggers generally when a variable is assigned an unquoted command name (from a list of hard coded names). See related warning SC2037 which detects the same kind of error through the patterns var=value -flag and var=value *glob*.

Related resources:

• BashFaq: How can I store the return value and/or output of a command in a variable?
• StackOverflow: How to set a variable to the output from a command in Bash

ShellCheck

• Installation

  • CentOS6
  • More Installation Guides

• Usage

  • Directive
  • Ignore

• Integrating and extending

  • Misc. contributions
  • Azure Pipelines
  • Buildkite
  • CircleCI
  • DevGuide
  • Integration
  • JUnit
  • Phabricator
  • TravisCI
  • GitLab CI
  • Drone
  • GitHub Actions

• Severity

• Template

Each individual ShellCheck warning has its own wiki page like SC1000. Use GitHub Wiki's "Pages" feature above to find a specific one, or see Checks.