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Use regex in replacement string in SED

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# 1  
Old 02-07-2012
Use regex in replacement string in SED
Hi,

I need to use the regex in the replacement string in SED command.
something like

Code:
sed -e ' s/\(^[A-Z]\{5\}\).\{150\}\(.*\)$/\10\{30\}1\{30\}A\{60\}B\{30\}\2/' abc

which means for all the lines in file abc that starts with 5 characters, I need to replace character 6-151 with...

Code:
*   30 occurances of '0'
*   30 occurances of '1'
*   60 Occurances of 'A'
*   30 occurances of 'B'

but, they are getting replaced with the hardcoded characters 0\{30\}1\{30\}A\{60\}B\{30\} instead. So how can I start using regex in the replacement string of SED command?

Thanx in advance
Last edited by Franklin52; 02-23-2012 at 04:24 AM.. Reason: Please use code tags for code and data samples, thank you
# 2  
Old 02-07-2012
Hi snowline84,

It is possible using sed, but there are better tools. Are you stuck with it?

See what an ugly script:
Code:
$ sed '
  1 { 
    x; 
    s/^.*$/00000000001111111111AAAAAAAAAABBBBBBBBBB/; 
    s/\(0\+\)\(1\+\)\(A\+\)\(B\+\)/\1\1\1\2\2\2\3\3\3\3\3\3\4\4\4/; 
    x 
  }; 
  /^\([A-Z]\{5\}\)/ { 
    G; 
    s/^\([A-Z]\{5\}\).\{150\}\(.*\)\n\(.*\)$/\1\3\2/ 
  }
' inputfile

Regards,
Birei
# 3  
Old 02-07-2012
Can you provide a more specific and desired output...

--ahamed
# 4  
Old 02-07-2012
Hi Ahmed,

I need to supress the information present in a file so, need to override specific 151 characters.
I usually use SED for my commands Smilie but didn't want to fire something this ugly

Code:
sed -e ' s/\(^[A-Z]\{5\}\).\{150\}\(.*\)$/\1000000000000000000000000000000111111111111111111111111111111AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\2/' abc > test

there must be a better way to do it.

Thanks
Last edited by Franklin52; 02-23-2012 at 04:24 AM.. Reason: Please use code tags for code and data samples, thank you
# 5  
Old 02-22-2012
HI Birei,

What other options do you suggest to achieve the same?
# 6  
Old 02-23-2012
Maybe Perl which has the repetition operator x.
Code:
perl -lne '$_ =~ s/(^[A-Z]{5}).{150}(.*)/$1 . '0' x30 . '1' x30 . 'A' x60 . 'B' x30 . $2/e; print' inputfile

If you want only with Sed then store the replacement values in a variable and use that variable in the Sed replacement part.
# 7  
Old 02-23-2012
Code:
v=$(echo '01AAB' | sed 's/./&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&/g')
sed "s/^\([A-Z]\{5\}\).\{150\}/\1$v/" infile

Smilie
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