Shell Programming and Scripting

awk '
# Define a function named printlist()
function printlist(     i) { # It has a local variable (i).
        for(i = 1; i <= c; i++) # For every line in the array l[], 
                printf("%s\n", l[i]) # print that line.
        print "" # Then print an empty line as a separator.
}
# If the 1st character on a line is '[',
/^[[]/ {if(c > 2) printlist() # if we have more than two lines saved, print the saved lines.
        c = 0 # Clear the number of saved lines no matter how many lines were saved before.
}
# If the input line is not empty,
/./ {   l[++c] = $0 # increment the number of saved lines (c) and save the current line.
}
# When we hit end-of-file,
END {   if(c > 2) printlist()  # if we have more than two lines saved, print the saved lines.
}' listing # Our input file is named "listing"

man 1 utility_name