Shell Programming and Scripting

>aa.txt
31
35
36
37
38
39    
44
169
170
173
174
175
177
206 
>1a.txt
39
40
41
42
146
149
151

>aa_1.txt
35
36 
37
38
39
>aa_2.txt
173
174
175
>1a.txt
39
40
41
42

sort -n filename.txt | head -3

awk '
        BEGIN {
                c = 1
        }
        {
                A[NR] = $1
        }
        END {
                for ( i = 1; i < NR; i++ )
                {
                        d = A[i+1] - A[i]

                        F = FILENAME
                        sub ( /\.txt/, "_" c ".txt", F )

                        if ( d == 1 )
                        {
                                printf "%d\n", A[i] > F
                                f = 1
                        }

                        if ( f && d != 1 )
                        {
                                printf "%d\n", A[i] > F
                                f = 0
                                c += 1
                        }
                }
        }
' aa.txt

arr=[]
with open("a.txt") as file:
 for line in file:
  line=line.replace("\n","")
  if not arr:
    arr.append(line)
  elif int(arr[-1])+1==int(line):
    arr.append(line)
  else:
    if len(arr)>=3:
        print("\n".join(arr))
        print("")
    arr=[line]        
    
if len(arr)>=3:
    print("\n".join(arr))