Tom Christiansen in 2008
|Born||February 13, 1963|
|Residence||Boulder, Colorado, U.S.|
|Employer||Tom Christiansen Perl Consultancy
Biomedical Text Mining Group, University of Colorado School of Medicine
|Known for||Perl writings|
Christiansen worked for several years at TSR Hobbies before attending the University of Wisconsin - Madison where he earned B.A.'s in Spanish and Computer Science, and an M.S. in Computer Science. He worked for five years at Convex Computer. In 1993, he established the Tom Christiansen Perl Consultancy, located in Lake Geneva, Wisconsin. In 2010, he joined the Biomedical Text Mining Group at the University of Colorado School of Medicine.
Christiansen, with a C-and-Unix background, was one of the early contributors to Perl after its public release in 1987. He presented the first public Perl tutorial in 1989 and wrote the first academic paper to highlight Perl in 1990. He was the author of much of the core Perl documentation, including the manual pages perlfaq and perltoot, development of perl.com. In 1996, Christiansen wrote "Csh Programming Considered Harmful" about the limitations inherent in C Shell Programming. Books he co-authored include:
- The second (1996) and third (2000) editions of Programming Perl.
- The second (1997) edition of Learning Perl (and its spin-off Learning Perl on Win32 Systems).
- The Perl Cookbook (1998).
In 1999, Christiansen was one of the original recipients of the White Camel awards from Perl Mongers for his contribution to Perl's documentation. Christiansen has been called a "Perl priest"  and a "UNIX luminary".
The common phrase "Only perl can parse Perl" is attributed to Tom Christiansen, although it probably was inspired from "Only tex can understand TeX". Randal Schwartz also credits him with accidentally naming the Schwartzian Transform for optimizing some types of sorts. This happened after Schwartz used it in a Usenet message, and Christiansen replied to the message giving some corrections and in one place said "the Schwartzian transform" to refer to the transform that Schwartz used.
- "Company Profile for Tom Christiansen Perl Consultancy". Manta (web site).
- "O'Reilly bio for Tom Christiansen". O'Reilly Media.
- Mark Jason Dominus. "Higher-Order Perl - Preface".
- "PerlTimeline". Retrieved 5 January 2013.
- "LISA'98 12th System Administration Conference - Tutorial instructors". USENIX. December 1998.
- "Csh Programming Considered Harmful". Retrieved 5 January 2013.
- Schwartz, Randall (1997). Learning Perl on Win32 Systems. Sebastopol, CA: O'Reilly Media. ISBN 978-1-56592-324-9.
- "White Camel Awards 1999 recipients". Perl.org. 1999.
- Xah Lee (1999). "Perl Books Survey 2002".
The three characteristics of Perl programers: mundaneness, sloppiness, and fatuousness. ... Perl provides the DWIM feature. DWIM stands for Dim Wit I Am, and is pronounced Dim Wit. It is a fashionable locution of the Perl Republic, trumpeted by priests like Tom Christiansen. Perl is a lousy hack used by sloppy unix sys admins. (because it's free). ... [Programming Perl] is the worst tech book ever written.
- Samuel Ockman (Sep 1, 1998). "UNIX Power Tools - review". Linux Journal.
- "Perl vs perl". Israeli Perl Mongers.
- Randal Schwartz. "Sorting with the Schwartzian Transform". CMP Media, LLC.
- (1999) "Plural of Virus"
- perl.com "The Seven Deadly Sins of Perl"
- UNIX faq - shell "Csh Programming Considered Harmful".
- (1991) "GUIs Considered Harmful". PerlMonks
- (1997) Interview with Tom Christiansen and Larry Wall, Web Review magazine, Feb 28, 1997 issue (link to archived copy)
- (2009) Redhat perl != perl (mailing list message)