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comparing big notebooks with diff

  • To: mathgroup at smc.vnet.net
  • Subject: [mg45344] comparing big notebooks with diff
  • From: Christopher Purcell <christopherpurcell at mac.com>
  • Date: Thu, 1 Jan 2004 05:54:35 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Too frequently I have to search for unintended changes I have made in  
large notebooks. If I am lucky I have a previous version to compare  
with. Here is an interface to the Unix (and Mac OSX) diff command,  
which I find useful, since it can compare huge files very fast. It  
would be great if some Notebook wizard would take this routine and add  
the possibility of opening both files being compared in nicely  
sized/positioned windows and color highlighting the differences. This  
also works on Windows if the Cygwin Unix emulator is installed. If not,  
the DOS command FC could probably be substituted for diff.

diff::usage="diff[file1,file2] provides an interface to the diff  
routine on Unix-like operating systems. The following command:
Transpose[Drop[Transpose[Flatten[Map[ReadList[StringToStream[#[[1]]],{Nu 
mber,Character,Number}]&,
Partition[diff[file1,file2],4] ],1] ],{2}]]
extracts just the pairs of line numbers of the files,that could be used  
as pointers if they were read with something like:
data1=ReadList[file1,Record,NullRecords->True];
data2=ReadList[file2,Record,NullRecords->True];
Here is an example of usage:
\"This statement is false\">>junk1.txt
\"This statement is true\">>junk2.txt
diff[\"junk1.txt\",\"junk2.txt\"] ";

diff[file1_String,file2_String]:=
Module[{log},(Run["diff"<>" "<> file1<>" "<> file2<>">"<>"diff.log"] ;
log=ReadList["diff.log",Record];DeleteFile["diff.log"];log)];


Christopher Purcell
Sensors & Actuators Group
DRDC-Atlantic, 9 Grove St., PO Box 1012,
Dartmouth NS B2Y 3Z7 Canada
Tel 902-426-3100 x389
Fax 902-426-9654



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