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regexgrepsunos

regex failed to match using {M,N} on SunOS

I have the following sample file and regular expression.

testing.txt

testing                  aa
a bc de
e                        aa
ba                        Z
testing                  bb
testing                  ac

my regular expression using egrep

egrep '[ ]{2,}' testing.txt

The above regular expression attempts to find contiguous white spaces in a line. However, the result returned is empty.

the regulartion expression below works for 1 or more spaces. However that is not what I want.

egrep '[ ]+' testing.txt
Solution

  • If your system is old, this help reference might be describing the issue:

    Traditional egrep did not support the { metacharacter, and some egrep implementations support \{ instead, so portable scripts should avoid { in egrep patterns and should use [{] to match a literal {.

    That means, that - if grep '[ ]\{2,\}' testing.txt does not work - you are better off using Perl or GNU grep to achieve what you want.

    Also, egrep '[ ][ ]+' testing.txt seems to be a workaround only in the current situation, and will not scale, but it certainly will help you for the time being.