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Top Forums UNIX for Dummies Questions & Answers using 'cat' to in 'while read line' Post 96206 by mahendramahendr on Wednesday 18th of January 2006 01:40:50 PM
Old 01-18-2006
Yes you can use perl, that would be better than bash..

But if there is any extra line in middle on any one file, then your script will show that all lines after that extra line are not matching though the data might match, because you are comparing data against exact line numbers. You need to put extra efforts here to match this kind of stuff like what diff unix command does, diff unix command won't match based on the line numbers...

Why can't you use unix diff command ?? here is an example


$ more datafile
abcdefghijklmnopqrstuvwxyz.
123456789009876543211234567
This line to be removed.
zyxwvutsrqponmlkjihgfedcba.

$ more datafile1
abcdefghijklmnopqrstuvwxyz.
1234567890098765432112345672
hello how are you
This line to be removed.
zyxwvutsrqponmlkjihgfedcba.4

$ $ diff datafile datafile1
2c2,3
< 123456789009876543211234567
---
> 1234567890098765432112345672
> hello how are you
4c5
< zyxwvutsrqponmlkjihgfedcba.
---
> zyxwvutsrqponmlkjihgfedcba.4



in the above diff, you can see (highlighted in bold)

<number>c<number>,<number>.......

i.e first number before character "c" is the line number from first file and numbers after "c" are numbers from 2nd file in diff command.

2c2,3 mean line number 2 in datafile is different from line numbers 2 and 3 in datafile1. Here you can see that line 3 in datafile1 is an extra line that is completly missing in datafile, so diff ignores this line and starts comparing datafile line 3 against datafile1 line 4.... not line 3 in datafile against line 3 in datafile 4.

You can actually egrep "^[0-9]*c[0-9]*[,0-9]*" or egrep -v "<|>|-" from the diff output, to get the lines which differ and the make use of it... based on the line numbers you can set the true or false..

not sure there is a simple way.. may be i can take a look if i find time
 

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bdiff(1)                                                           User Commands                                                          bdiff(1)

NAME
bdiff - big diff SYNOPSIS
bdiff filename1 filename2 [n] [-s] DESCRIPTION
bdiff is used in a manner analogous to diff to find which lines in filename1 and filename2 must be changed to bring the files into agree- ment. Its purpose is to allow processing of files too large for diff. If filename1 (filename2) is -, the standard input is read. bdiff ignores lines common to the beginning of both files, splits the remainder of each file into n-line segments, and invokes diff on cor- responding segments. If both optional arguments are specified, they must appear in the order indicated above. The output of bdiff is exactly that of diff, with line numbers adjusted to account for the segmenting of the files (that is, to make it look as if the files had been processed whole). Note: Because of the segmenting of the files, bdiff does not necessarily find a smallest sufficient set of file differences. OPTIONS
n The number of line segments. The value of n is 3500 by default. If the optional third argument is given and it is numeric, it is used as the value for n. This is useful in those cases in which 3500-line segments are too large for diff, causing it to fail. -s Specifies that no diagnostics are to be printed by bdiff (silent option). Note: However, this does not suppress possible diagnos- tic messages from diff, which bdiff calls. USAGE
See largefile(5) for the description of the behavior of bdiff when encountering files greater than or equal to 2 Gbyte ( 2**31 bytes). FILES
/tmp/bd????? ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWesu | +-----------------------------+-----------------------------+ |CSI |enabled | +-----------------------------+-----------------------------+ SEE ALSO
diff(1), attributes(5), largefile(5) DIAGNOSTICS
Use help for explanations. SunOS 5.10 14 Sep 1992 bdiff(1)
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