! negation operator (see negation operator)
( ) (parentheses):  3. Unary and Binary Operators (Programming Perl)
  -  3.1. Terms and List Operators (Leftward) (Programming Perl)
-  24.1.1. Universal Blunders (Programming Perl)
-  24.3. Programming with Style (Programming Perl)
- around function arguments:  5. Function Reference (Perl in a Nutshell)
- for backreferences:  1.7.4. Backreferences (Programming Perl)
- 
    -  5.7.1. Capturing (Programming Perl)
-  5.7.1. Capturing (Programming Perl)
 
- conditional operator, use with:  3.16. Conditional Operator (Programming Perl)
- in functions:  29. Functions (Programming Perl)
- grouping operator:  5.1. The Regular Expression Bestiary (Programming Perl)
- null lists, representing:  2.8. List Values and Arrays (Programming Perl)
- metacharacter:  5.1. The Regular Expression Bestiary (Programming Perl)
- 
    -  5.3. Metacharacters and Metasymbols (Programming Perl)
 
- operator precedence and:  4.5. Operators (Perl in a Nutshell)
- (...) grouping:  5.3.1. Metasymbol Tables (Programming Perl)
- (?:PATTERN) notation, clustering without capturing:  5.7.2. Clustering (Programming Perl)
- 
    -  5.7.2. Clustering (Programming Perl)
 
- as quote characters:  2.8. List Values and Arrays (Programming Perl)
- regular expression metacharacter:  4.6.2. Regular Expression Syntax (Perl in a Nutshell)
- (?...) extended regular expression syntax:  4.6.8. Extended Regular Expressions (Perl in a Nutshell)
% (percent sign):  3.10. Named Unary and File Test Operators (Programming Perl)
  
  - %SIG:  4.10. Signals (Perl in a Nutshell)
- for checksums:  29.2.189. unpack (Programming Perl)
- dereferencing with:  4.8.2. Dereferencing (Perl in a Nutshell)
- for hash names:  1.2.1.2.2. Hashes. (Programming Perl)
- 
    -  2.4. Variables (Programming Perl)
 
- modulus operator:  4.5.3. Arithmetic Operators (Perl in a Nutshell)
- 
    -  3.7. Multiplicative Operators (Programming Perl)
 
- %= (modulus assignment) operator:  3.17. Assignment Operators (Programming Perl)
- prototype character:  6.4. Prototypes (Programming Perl)
- prototype symbol (hash):  4.7.5. Prototypes (Perl in a Nutshell)
- signifying variable type:  4.2.5.2. Hashes (Perl in a Nutshell)
- 
    -  1.2.1. Variable Syntax (Programming Perl)
 
- %= (assignment) operator:  4.5.6. Assignment Operators (Perl in a Nutshell)
| pipe:  11.1. What Is a Filehandle? (Learning Perl)
  -  14.5. Processes as Filehandles (Learning Perl)
+ (plus):  3.10. Named Unary and File Test Operators (Programming Perl)
  
-  7.2.2. Simple Quantifiers (Learning Perl)
-  4.5.5. Autoincrement and Autodecrement (Perl in a Nutshell)
- additive operator:  3.8. Additive Operators (Programming Perl)
- in filenames:  29.2.104. open (Programming Perl)
- ++ (autoincrement) operator:  1.5.4. Unary Arithmetic Operators (Programming Perl)
- 
    -  3.3. Autoincrement and Autodecrement (Programming Perl)
 
- quantifier:  1.7. Regular Expressions (Programming Perl)
- regular expression metacharacter:  4.6.2. Regular Expression Syntax (Perl in a Nutshell)
- unary operator:  4.5.2. Unary Operators (Perl in a Nutshell)
- += (assignment) operator:  4.5.6. Assignment Operators (Perl in a Nutshell)
$!, portability of:  25.4. System Interaction (Programming Perl)
# pound sign:  1.4.2. What's Inside That Program? (Learning Perl)
? (question mark)
  
  - metacharacter:  5.1. The Regular Expression Bestiary (Programming Perl)
- 
    -  5.3. Metacharacters and Metasymbols (Programming Perl)
 
- quantifier:  1.7.1. Quantifiers (Programming Perl)
- 
    -  5.3.1. Metasymbol Tables (Programming Perl)
 
- in quantifiers:  5.5. Quantifiers (Programming Perl)
- ?: (conditional) operator:  3.16. Conditional Operator (Programming Perl)
- 
    -  4.5.1. Case Structures (Programming Perl)
 
- ?? quantifier:  5.3.1. Metasymbol Tables (Programming Perl)
- regular expression metacharacter:  4.6.2. Regular Expression Syntax (Perl in a Nutshell)
- ?: (conditional) operator:  4.5.11.2. Conditional operator (Perl in a Nutshell)
- ?...? pattern match operator:  4.6.1. Pattern-Matching Operators (Perl in a Nutshell)
- ?...? Perl debugger command:  6.2. Debugger Commands (Perl in a Nutshell)
**= raise to the power of operator:  2.5.3. Binary Assignment Operators (Learning Perl)
.. range operator:  3.3. List Literals (Learning Perl)
; (semicolon)
  
-  3.1. XML Parsers (Perl & XML)
- ending Perl statements:  4.1. Program Structure (Perl in a Nutshell)
- in filenames, security risks of:  23.1.2. Cleaning Up Your Environment (Programming Perl)
- Perl statements, terminating with:  2.2. Molecules (Programming Perl)
- in prototype declarations:  4.7.5. Prototypes (Perl in a Nutshell)
- simple statements, ending in:  4.1. Simple Statements (Programming Perl)
\038 (octal value) sequence:  4.6.3. Escaped Sequences (Perl in a Nutshell)
/ (slash):  3.10. Named Unary and File Test Operators (Programming Perl)
  
  - debugger command:  20.2.5. Locating Code (Programming Perl)
- delimiters, replacing as:  2.6.3. Pick Your Own Quotes (Programming Perl)
- division operator:  4.5.3. Arithmetic Operators (Perl in a Nutshell)
- 
    -  3.7. Multiplicative Operators (Programming Perl)
 
- encoding in URLs:  9.2. URL Encoding (Perl in a Nutshell)
- / (root directory):  9.0. Introduction  (Perl Cookbook)
- root directory:  29.2.15. chroot (Programming Perl)
- /=; (assignment) operator:  3.17. Assignment Operators (Programming Perl)
- // (see m// operator)
- /= (assignment) operator:  4.5.6. Assignment Operators (Perl in a Nutshell)
- /.../ pattern match operator:  4.6. Regular Expressions (Perl in a Nutshell)
- /.../ Perl debugger command:  6.2. Debugger Commands (Perl in a Nutshell)
-  2.9. Free-Form XML and Well-Formed Documents (Perl & XML)
- well-formed documents and:  3.1.1. Example (of What Not to Do): A Well-Formedness Checker (Perl & XML)
- XPath expressions:  8.2. XPath (Perl & XML)
* star:  7.2.2. Simple Quantifiers (Learning Perl)
?: ternary operator:  10.9.2. The Ternary Operator, ?: (Learning Perl)
~ (tilde)
  
  - bitwise negation operator:  4.5.2. Unary Operators (Perl in a Nutshell)
- 
    -  3.5. Ideographic Unary Operators (Programming Perl)
 
- to suppress blank lines:  7. Formats (Programming Perl)
- suppressing output whitespace:  4.12. Formats (Perl in a Nutshell)
- ~~ to print strings in fields:  4.12. Formats (Perl in a Nutshell)
-  12.1. Moving Around the Directory Tree (Learning Perl)
_ underscore:  2.2.3. Integer Literals (Learning Perl)
  -  4.10. The use strict Pragma (Learning Perl)
$0 variable:  6.3. The Invocation Arguments (Learning Perl)
  -  11.3. Fatal Errors with die (Learning Perl)
| (vertical bar)
  
-  7.2.4. Alternatives (Learning Perl)
- for alternation:  5.1. The Regular Expression Bestiary (Programming Perl)
- bitwise or operator:  3.13. Bitwise Operators (Programming Perl)
- for centering:  7.1. Format Variables (Programming Perl)
- debugger command:  20.2.6. Actions and Command Execution (Programming Perl)
- ...|... alternation:  5.3.1. Metasymbol Tables (Programming Perl)
- in filenames:  29.2.104. open (Programming Perl)
- format fieldholders:  4.12. Formats (Perl in a Nutshell)
- -| piping pseudocommand:  16.3.2. Talking to Yourself (Programming Perl)
- metacharacter:  5.1. The Regular Expression Bestiary (Programming Perl)
- 
    -  5.3. Metacharacters and Metasymbols (Programming Perl)
 
- OR bitwise operator:  4.5.10. Bitwise Operators (Perl in a Nutshell)
- Perl debugger command:  6.2. Debugger Commands (Perl in a Nutshell)
- regular expression metacharacter:  4.6.2. Regular Expression Syntax (Perl in a Nutshell)
- || (logical or) operator:  5.9.1. Letting Perl Do the Work (Programming Perl)
- 
    -  12.3.3. Syntactic Snafus with Indirect Objects (Programming Perl)
 
- || (OR logical operator): 1.5.5. Logical Operators 
  (Programming Perl) 
  - |- piping pseudocommand:  16.3.2. Talking to Yourself (Programming Perl)
- || debugger command:  20.2.6. Actions and Command Execution (Programming Perl)
- |= (assignment) operator:  4.5.6. Assignment Operators (Perl in a Nutshell)
- 
    -  3.17. Assignment Operators (Programming Perl)
 
- || (logical OR) operator:  4.5.9. Logical Operators (Perl in a Nutshell)
- ||= (assignment) operator:  4.5.6. Assignment Operators (Perl in a Nutshell)
- 
    -  3.17. Assignment Operators (Programming Perl)
 
Numbers
- 0+ (numification) operator:  13.3. Overloadable Operators (Programming Perl)
- "0 but not true":  10.10.3. Discussion  (Perl Cookbook)
- 
  -  17.2.3. Discussion  (Perl Cookbook)
-  17.2.3. Discussion  (Perl Cookbook)
 
- 0 but true:  29.2.37. fcntl (Programming Perl)
- 
  
  -  -w exemption:  29.2.37. fcntl (Programming Perl)
 
- \038 (octal value) sequence:  4.6.3. Escaped Sequences (Perl in a Nutshell)
- "500 Server Error", fixing:  19.3.1. Problem (Perl Cookbook)
Symbols
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| B
| C
| D
| E
| F
| G
| H
| I
| J
| K
| L
| M
| N
| O
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| R
| S
| T
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