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Why double "\" required?

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# 1  
Old 04-09-2018
Why double "\" required?
Hi Gurus,

Below command give error if i put single "\", If I put two, it works. my understanding is: we can use "\" to escapt the special characters. why here I need to put two "\". The system I am working on is SunOS 5.10 Generic_150400-04 sun4v sparc sun4v

Code:
echo "SUCCESS(ABCD)" |nawk '{gsub("SUCCESS\\(", "")}1'
ABCD)

echo "SUCCESS(ABCD)" |nawk '{gsub("SUCCESS\(", "")}1'
nawk: illegal primary in regular expression SUCCESS( at 
 source line number 1
 context is
        {gsub("SUCCESS\(", >>>  "") <<<

Last edited by rbatte1; 04-09-2018 at 01:43 PM.. Reason: Added CODE tags
# 2  
Old 04-09-2018
It is because awk substitutes \ in strings. For example
Code:
nawk 'BEGIN {print "\a"}' </dev/null
nawk 'BEGIN {print "\b"}' </dev/null

So within " " you need \\ for a literal \
Therefore, you better have regular expressions in / /
Code:
echo "SUCCESS(ABCD)" | nawk '{gsub(/SUCCESS\(/, "")}1'

This User Gave Thanks to MadeInGermany For This Post:
green_k
# 3  
Old 04-09-2018
Hello green_k,

\\( means escape \ to remove its special meaning. If you will put ( without \ will be treated as sub's starting ( parenthesis and it will give error.

Thanks,
R. Singh
This User Gave Thanks to RavinderSingh13 For This Post:
green_k
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