TLDR Search

Enter a command. For example: git tag, httprobe, is up, docker run.

expr

Evaluate expressions and manipulate strings. More information: https://www.gnu.org/software/coreutils/expr.

• Get string length:
   
  expr length {{string}}
   
• Evaluate logical or math expression with an operator ('+', '-', '*', '&', '|', etc.). Special symbols should be escaped:
   
  expr {{first_argument}} {{operator}} {{second_argument}}
   
• Get position of the first character in 'string' that matches 'substring':
   
  echo $(expr index {{string}} {{substring}})
   
• Extract part of the string:
   
  echo $(expr substr {{string}} {{position_to_start}} {{number_of_characters}}
   
• Extract part of the string which matches a regular expression:
   
  echo $(expr {{string}} : '\({{regular_expression}}\)')