sed - Adding a text from one file when finding a match on another file -

i search through many answers , not find on it.

i have text file (from exam) , answers in file. managed add text "answer: " @ end of each question, cannot find way pick answer file2 file1.

file1:

question: 179 – alterando-se o ângulo de ataque de 0º para 6º, resistência parasita:

a aumenta  b) não se altera  c) diminui  d) impossível de se determinar  answer: 

file2:

177)c 178)a 179)b 180)b 

i tried use sed far no success, suggestion appreciated.

the file1 structure repeats every question, questions can have more 1 line.

the desired output should be:

question: 179 – alterando-se o ângulo de ataque de 0º para 6º, resistência parasita:

a aumenta  b) não se altera  c) diminui  d) impossível de se determinar  answer: b 

sed hardly tool of choice this, whereas reasonably easy in awk.

awk 'nr==fnr {         # nr equal fnr when reading first input file         # store right answer each question in array         split($1, b, /\)/)         # if input 123)a, array b contains "123" , "a"         a[b[1]] = b[2]         # done; skip next line         next     }     # if here, in second file.  find question delimiter     /question: [0-9]+/ {         # if have previous question in memory, print answer first         if (q>0) { print "\nanswer: " a[q] "\n\n" }         # remember index question         q=$2     }     # if far, perform default action, is, print line     # "1" shorthand "print current line"     1     # @ end of file, print last remaining answer     end { print "\nanswer: " a[q] "\n\n" }' file2 file1 

this isn't entirely robust if format of question header or data in answers file isn't regular, though.