GAWK: Effective AWK Programming

314 GAWK: Effective AWK ProgrammingShort-CircuitThe nature of the awk logical operators ‘&&’ and ‘||’. If the value of the entireexpression is determinable from evaluating just the lefthand side of theseoperators, the righthand side is not evaluated. (See Section 5.11 [Boolean Expressions],page 91.)Side EffectA side effect occurs when an expression has an effect aside from merely producinga value. Assignment expressions, increment and decrement expressions,and function calls have side effects. (See Section 5.7 [Assignment Expressions],page 83.)Single-PrecisionAn internal representation of numbers that can have fractional parts. Singleprecisionnumbers keep track of fewer digits than do double-precision numbers,but operations on them are sometimes less expensive in terms of CPU time.This is the type used by some very old versions of awk to store numeric values.It is the C type float.SpaceThe character generated by hitting the space bar on the keyboard.Special FileA file name interpreted internally by gawk, instead of being handed directly tothe underlying operating system—for example, ‘/dev/stderr’. (See Section 4.7[Special File Names in gawk], page 69.)Stream EditorA program that reads records from an input stream and processes them one ormore at a time. This is in contrast with batch programs, which may expect toread their input files in entirety before starting to do anything, as well as withinteractive programs which require input from the user.StringTabA datum consisting of a sequence of characters, such as ‘I am a string’. Constantstrings are written with double quotes in the awk language and maycontain escape sequences. (See Section 2.2 [Escape Sequences], page 25.)The character generated by hitting the TAB key on the keyboard. It usuallyexpands to up to eight spaces upon output.Text DomainA unique name that identifies an application. Used for grouping messages thatare translated at runtime into the local language.TimestampUnixA value in the “seconds since the epoch” format used by Unix and POSIXsystems. Used for the gawk functions mktime, strftime, and systime. Seealso “Epoch” and “UTC.”A computer operating system originally developed in the early 1970’s at AT&TBell Laboratories. It initially became popular in universities around the worldand later moved into commercial environments as a software development systemand network server system. There are many commercial versions of Unix,