just a tip

[[email protected] tmp]# echo `seq 100`
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

[[email protected] tmp]# seq 100 > ett.txt
[[email protected] tmp]# ls
ett.txt

[[email protected] tmp]# sed -n 20,30p
^C
[[email protected] tmp]# sed -n 20,30p ett.txt
20
21
22
23
24
25
26
27
28
29
30

[[email protected] tmp]# sed -n 30p ett.txt
30

awk: {if(NR>19)&&(NR<31)print $0}
awk:                    ^ syntax error
[[email protected] tmp]# awk ‘{if\(NR>19\)&&\(NR<31\)print $0}‘ ett.txt
awk: {if\(NR>19\)&&\(NR<31\)print $0}
awk:    ^ backslash not last character on line
[[email protected] tmp]# awk ‘{if(NR>19)&&(NR<31) print $0}‘ ett.txt
awk: {if(NR>19)&&(NR<31) print $0}
awk:           ^ syntax error
awk: {if(NR>19)&&(NR<31) print $0}
awk:                     ^ syntax error
[[email protected] tmp]# awk ‘{if(NR>19 &&NR<31) print $0}‘ ett.txt
20
21
22
23
24
25
26
27
28
29
30

[[email protected] tmp]# head -30 ett.txt |tail -11
20
21
22
23
24
25
26
27
28
29
30