Zsh parameter expansion flags are powerful tools that enhance shell scripting capabilities by providing advanced string manipulation and pattern matching. They allow for more concise, readable scripts, reducing the need for external commands like sed or awk.
The syntax is ${parameter:#pattern}, where ‘parameter’ is the variable name and ‘pattern’ is what you’re searching for. The ‘#’ flag removes the shortest match of ‘pattern’ from the start of ‘parameter’. For instance, if VAR=”HelloWorld”, then ${VAR:#Hell} would return “oWorld”.
Another useful flag is ‘%’, which operates similarly but removes from the end. So, ${VAR:%World} would return “Hello”.
For longer matches, ‘##’ and ‘%%’ can be used. These remove the longest match from the start or end respectively.
There’s also ‘=()’ for splitting strings into arrays based on a delimiter, and ‘P’ for indirect referencing.
These flags provide greater control over data manipulation within Zsh scripts, enhancing efficiency and readability.
