function::returnstr - Linux


function::returnstr is a powerful command-line utility designed to parse strings based on user-defined functions. It enables users to extract, modify, or convert specific segments of a string using custom logic. This command is particularly useful in data manipulation, scripting, and text processing tasks, empowering users to automate complex string transformations.


function::returnstr <function> <string> [options]


  • function: The user-defined function to apply to the string.
  • string: The input string to be processed.


  • -h, –help: Display the usage information and exit.
  • -d, –delimiter: Specify the delimiter to use for parsing the string (default: comma).
  • -o, –output: Set the output format (default: text).
    JSON, CSV, XML, and YAML are supported.
  • -e, –escape: Specify the escape character used for special characters (default: backslash).
  • -i, –ignore-case: Ignore case distinctions in the string comparison.


Extracting a substring

To extract the first five characters from a string, use:

function::returnstr substring:5 my_string

Converting to uppercase

To convert all characters in a string to uppercase, use:

function::returnstr toupper: my_string

Removing duplicate words

To remove duplicate words from a string, use a custom function and delimiter:

function::returnstr unique_words:\| my_string

Common Issues

Syntax errors

Ensure that the function syntax aligns with the expected format: <function_name>:<parameter>.

Incorrect output format

Verify that the specified output format (-o) matches the desired result type (e.g., JSON, CSV).


function::returnstr can be integrated with other Linux commands using pipes:

echo "my,string" | function::returnstr split:"," -o csv | sort

Related Commands

  • sed – A stream editor for text manipulation.
  • awk – A pattern scanning and processing language.
  • grep – A utility for searching and filtering text.

For more information, refer to the official documentation: