Implementation of Linux under OD-TX-TC xxx function

Implementation of Linux under OD-TX-TC xxx function one, od command (1) function

The OD command is used to display the specified file contents in eight-, decimal, 16-, floating-point, or ASCII-encoded characters, and is typically used to display or view characters in a file that cannot be displayed directly in the terminal.

Common files are text files and binary files. The OD command is used primarily to view the values stored in a binary file, interpret the data in the file in the specified format, and output it.

(2) command format

od [<选项><参数>] [<文件名>]

(3) Command options

-t<TYPE>: Specify the output format, including a, C, D, F, O, U, and X, meaning the following:

• A: a name character;
• C:ascii characters or backslash;
• D[size]: decimal, positive negative numbers are included, SIZE bytes form a decimal integer;
• F[size]: Floating point, SIZE byte consists of a floating-point number;
• O[size]: octal, SIZE byte consists of an octal number;
• U[size]: Unsigned decimal, contains only positive numbers, and SIZE bytes form an unsigned decimal integer;
• X[size]: 16 binary, size byte is the hexadecimal output, which is the output when a column contains a SIZE byte. By default, a set of four bytes of output

Second, the problem analysis

od -tx Fileis to output the contents of file in hexadecimal, which is displayed as a group of four bytes by default.

od -tc FileASCII value corresponding to output byte

In the title, the output od -tx -tc File byte corresponds to the ASCII value, which differs from the order of the output when the file content is output in hexadecimal. od -tc -tx File

Third, Myod.java

Import java.io.*;p ublic class myod{public static void Main (string[] args) throws IOException {try (fileinputst            Ream input = new FileInputStream ("/home/darkeye/cxgg20165312/20165312/hello")) {byte[] data = new byte[1024];            int i, flag;            Input.read (data);  for (i = 0; i < 1024x768; i = i + 4) {if (i% = = 0) {System.out.printf ("\n%07o\t\t",                i); }//Four bytes in one group and four groups in a row.                I=16 is the first column on the left (the default address), formatted as a seven-bit octal. By finding the rule, its value is the octal number corresponding to the ordinal value of the first character of the line (from 0 to length-1) System.out.printf ("%02x%02x%02x%02x\t", Data[i + 3], data[i                + 2], Data[i + 1], data[i]);                    if ((i + 4)% = = 0) {System.out.println ();                    System.out.printf ("\ t"); for (int j = i-12; J < I+4; J + +) {if (int) data[j] = =) {Syst                            em.out.printf ("\ \"); System.out.printf ("n ");                        } else {System.out.printf ("%c", Data[j]);                    }}} if (Data[i+4] ==0) {System.out.println ();                    System.out.printf ("\ t"); for (int j = i-i%16; data[j-3]! = 0; j + +) {if (int) data[j] = =) {S                            ystem.out.printf ("\ \");                        System.out.printf ("n");                        } else {System.out.printf ("%c", Data[j]);                }} break;        }} System.out.printf ("\n%07o\n", i+3); }    }}

Implementation of Linux under OD-TX-TC xxx function