Programming Ruby 3.3

Expressions, Conditionals, and Loops

Single terms in an expression may be any of the following:

• Literal. Ruby literals are boolean, numbers, strings, arrays, hashes, ranges, symbols, and regular expressions. These are described in ​Ruby Literals​.

• Shell command. A shell command is a string enclosed in backquotes or in a general delimited string starting with %x. The string is executed using the host operating system’s standard shell, and the resulting standard output stream is returned as the value of the expression. The execution also sets the $? variable with the command’s exit status:

filter = "*.c"
files = `ls #{filter}`
files = %x{ls #{filter}}

• Variable reference or constant reference. A variable is referenced by citing ...