SC2188.md

Pattern: Use of redirection that doesn't redirect from/to anything

Issue: -

Description

ShellCheck found a redirection that doesn't actually redirect from/to anything.

This could indicate a bug, such as in the problematic code where an additional linefeed causes report.txt to be truncated instead of containing report output, or in foo & > bar, where either foo &> bar or foo > bar & was intended.

However, it could also be intentionally used to truncate a file or check that it's readable. You can make this more explicit for both ShellCheck and human readers by using true or : as a dummy command, e.g. true > file or : > file.

Example of incorrect code:

{ 
  echo "Report for $(date +%F)"
  uptime
  df -h
}
> report.txt

Example of correct code:

{ 
  echo "Report for $(date +%F)"
  uptime
  df -h
} > report.txt

Exceptions

There are no semantic problems with using > foo over true > foo, so if you don't see this as a potential source of bugs or confusion, you can ignore it.

Further Reading

• ShellCheck - SC2188