Best way to add path to PATH environment variable

Solution

if [[ ! "$PATH" == *your_path* ]]; then
  PATH="${PATH:+${PATH}:}your_path"
fi

Explanation

[[ ! "$PATH" == *your_path* ]] checks if PATH contains your new path already, hence avoiding duplicates. This does not work well for nested bin directories, but that rarely happens.

${parameter:+word} uses word if parameter is null or unset. Therefore, if PATH is unset, no additional : is added before your new path.

References

• bash(1)