test.txt内容
asdfsg ewtwfsdf1Hello World!
hexdump -Cv test.txt 输出
00000000 61 73 64 66 73 67 20 65 77 74 77 66 73 64 66 31 |asdfsg ewtwfsdf1| 00000010 48 65 6c 6c 6f 20 57 6f 72 6c 64 21 0a |Hello World!.| 0000001d