The A-Z of Programming Languages: AWK
- — 27 May, 2008 09:43
Computer scientist and compiler expert Alfred V. Aho is a man at the forefront of computer science research. He has been involved in the development of programming languages from his days working as the vice president of the Computing Sciences Research Center at Bell Labs to his current position as Lawrence Gussman Professor in the Computer Science Department at Columbia University.
As well as co-authoring the 'Dragon' book series; Aho was one of the three developers of the AWK pattern matching language in the mid-1970's, along with Brian Kernighan and Peter Weinberger.
Computerworld recently spoke to Professor Aho to learn more about the development of AWK, in the first of a series of investigations into the most widely-used programming languages.
How did the idea/concept of the AWK language develop and come into practice?
As with a number of languages, it was born from the necessity to meet a need. As a researcher at Bell Labs in the early 1970s, I found myself keeping track of budgets, and keeping track of editorial correspondence. I was also teaching at a nearby university at the time, so I had to keep track of student grades as well.
I wanted to have a simple little language in which I could write one- or two-line programs to do these tasks. Brian Kernighan, a researcher next door to me at the Labs, also wanted to create a similar language. We had daily conversations which culminated in a desire to create a pattern-matching language suitable for simple data-processing tasks.
We were heavily influenced by GREP, a popular string-matching utility on UNIX, which had been created in our research center. GREP would search a file of text looking for lines matching a pattern consisting of a limited form of regular expressions, and then print all lines in the file that matched that regular expression.
We thought that we'd like to generalize the class of patterns to deal with numbers as well as strings. We also thought that we'd like to have more computational capability than just printing the line that matched the pattern.
So out of this grew AWK, a language based on the principle of pattern-action processing. It was built to do simple data processing: the ordinary data processing that we routinely did on a day-to-day basis.. We just wanted to have a very simple scripting language that would allow us, and people who weren't very computer savvy, to be able to write throw-away programs for routine data processing.