Question

I have a file:

@Book{gjn2011ske, 
  author =   {Grzegorz J. Nalepa},
  title =    {Semantic Knowledge Engineering. A Rule-Based Approach},
  publisher =    {Wydawnictwa AGH},
  year =     2011,
  address =  {Krak\'ow}
}

@article{gjn2010jucs,
  Author =   {Grzegorz J. Nalepa},
  Journal =  {Journal of Universal Computer Science},
  Number =   7,
  Pages =    {1006-1023},
  Title =    {Collective Knowledge Engineering with Semantic Wikis},
  Volume =   16,
  Year =     2010
}

I want to improve the regular expression that only removed the first line. Note: The record separator RS="}\n" can not be changed.

I tried:

awk 'BEGIN{ RS="}\n" } {gsub(/@.*,/,"") ; print }' file

I want to print the result:

  author =   {Grzegorz J. Nalepa},
  title =    {Semantic Knowledge Engineering. A Rule-Based Approach},
  publisher =    {Wydawnictwa AGH},
  year =     2011,
  address =  {Krak\'ow}

  Author =   {Grzegorz J. Nalepa},
  Journal =  {Journal of Universal Computer Science},
  Number =   7,
  Pages =    {1006-1023},
  Title =    {Collective Knowledge Engineering with Semantic Wikis},
  Volume =   16,
  Year =     2010

Thank you for your help.

EDIT:

My proposed solution:

awk 'BEGIN{ RS="}\n" }{sub(",","@"); sub(/@.*@/,""); print }' file 

Answer 1

It’s hard to accomplish what you want with the specified RS setting (because the address = {Krak\'ow} has an extra record ending). I’d rather go with:

awk '$0 !~ "^@" && $0 !~ "^} *$" { print }' FILE 

See it in action here.

EDIT I don’t know why it must be with a regexp solution, could you please explain it?

Anyway, yet another (working, see here) solution which uses regexp(s), but not the ones you are expecting.:

awk 'BEGIN{ RS="}\n" }
{
  split($0,a,"\n")
  for (e=1;e<=length(a);e++) {
      if (a[e] ~ "{" && a[e] !~ "}") {
          sub("$","}",a[e])
      }
      if (a[e] ~ "=") { print a[e] }
  }
  printf("\n")
}' INPUTFILE

One more, with a much simpler regexp, but it fails, with the “address” line as the last } will be removed with your RS, and it will print a final }…

awk 'BEGIN{ RS="}\n" }
{
  sub("@[^,]\+,","")
  print $0
}' INPUTFILE