Awk - how to print variable with string

Question

I have this input and I would like to learn how to save string after = to variable and use it for output filename and in the first line of output that will start with \"#\"

Answer 1

Could you please try following. On the very first line this will add values of column2 line, RedNumDa line with hash and then with a new line it will print actual line.

awk '
/ROIysiz/{
  second_out=$NF
}
/RedNumDa/{
  first_line_value=$NF
}
/c column3/{
  third_part=$NF
}
/column2/{
  close(out_file)
  found=count=""
  first_part=$NF
  out_file=first_part second_out third_part
  next
}
/end header/{
  found=1
  next
}
found && out_file{
  if(++count==1){
    print "#" first_part OFS first_line_value ORS $0 > (out_file)
  }
  else{
    print > (out_file)
  }
}
' Input_file

Explanation: Adding detailed explanation for above code.

awk '                                              ##Starting awk program from here.
/ROIysiz/{                                         ##Checking condition if a line contains string ROIysiz then do following.
  second_out=$NF                                   ##Creating variable second_out for output file 2nd part.
}
/RedNumDa/{                                        ##Checking condition if line contains RedNumDa string in it.
  first_line_value=$NF                             ##Creating variable first_line_value for output file 1st part.
}
/c column3/{                                       ##Checking condition if line contains column 3 string in it.
  third_part=$NF                                   ##Creating variable third_part and setting its value to last field of current line.
}
/column2/{                                         ##Checking condition if line contains column2 string in it.
  close(out_file)                                  ##Closing out_file to avoid "too many files opened" error.
  found=count=""                                   ##Nullifying variable found here.
  first_part=$NF                                   ##Creating variable first_part which has last part of current line as value.
  out_file=first_part second_out third_part        ##Creating variable out_file which is having last field of current line and second_out variable value.
  next                                             ##next will skip all further statements from here.
}
/end header/{                                      ##Checking condition if string end header is found then do following.
  found=1                                          ##Setting variable found to 1 here.
  next                                             ##next will skip all further statements from here.
}
found && out_file{                                 ##Checking condition if found AND out_file is SET then do following.
  if(++count==1){                                  ##If count==1 then do following, to add # in starting of first line.
     print "#" first_part OFS first_line_value ORS $0 > (out_file)  ##Printing # and first_part OFS first_line_value ORS $0.
  }
  else{                                            ##Else if count is greater than 1 then do following.
    print > (out_file)                             ##Printing current line to out_file here.
  }
}
' Input_file                                       ##Mentioning Input_file name here.