Editing variable

A '''variable''' is a symbolic name associated with a [[value]]. A variable acts as a container and the [[value]] it contains may be changed from within a running [[program]], enabling data manipulation to take place from within the [[script]]. == Variables are dynamic == In [[awk]] variables are [[dynamic]] and can hold either [[numeric]] or [[string]] values. === Variables do not need predefinition prior to use === In awk, there is no need to declare or initialize variables before they are used. By default, variables are initialized to the [[empty]] string, which evaluates to [[zero]] when [[convert]]ed to a [[number]]. == Initialization within a begin block is possible == It is possible to initialize variables in a BEGIN block to make them obvious and to make sure they have proper initial values. === Variable names === As in most programming languages, the name of a variable must be a sequence of [[letter]]s, [[digit]]s, or [[underscore]] symbols, and may not begin with a [[digit]]. The awk interpreter is [[case sensitive]]. This means that variable names that have different letter cases are distinct and separate from each other: {{{ # The identifiers dog,Dog and DOG represent separate variables BEGIN { dog = "Benjamin" Dog = "Samba" DOG = "Bernie" printf "The three dogs are named %s, %s and %s.\n", dog, Dog, DOG } }}} === Special variables === Some names are used for [[special variable]]s. === Variables in awk do not need a sigil === In awk, variables are referenced using only the variable name and no [[sigil]] prefix is used before the variable name: {{{ sh awk '{var="foo";print var}' }}} === Variable names inside string constants are not expanded in awk === Secondly, [[awk]] does not behave like the Unix [[shell]]. Variables inside string constants are not expanded. The [[interpreter]] has no way to distinguish words in a string constant from variable names, so this would never be possible. So "hello name" is a constant string, regardless of whether name is a variable in the AWK script. New strings can be constructed from string constants and variables, using [[concatenation]]: {{{ awk # print the concatenation of a string and a variable directly print "hello " name; # concatenate, assign to 'newstr' and print that newstr = "hello " name; print newstr; }}} If the print statement is given several arguments (that is, they are separated by ","), it prints them separated by the OFS variable. So, presuming OFS is " ", the following is the equivalent to the first example above: {{{ awk print "hello", name; }}}

Summary:

This change is a minor edit.

Username: