Script Bash - Lire Un Fichier Binaire

Vous pouvez utiliser od (plus de la tête et awk pour un peu de post-traitement) pour cela. Pour obtenir l'année:

year=$(od -t x2 --skip-bytes=6 --read-bytes=2 file.moi | head -1 | awk '{print $2}')

Pour le mois:

month=$(od -t x1 --skip-bytes=8 --read-bytes=1 file.moi | head -1 | awk '{print $2}')

Et le jour:

day=$(od -t x1 --skip-bytes=9 --read-bytes=1 file.moi | head -1 | awk '{print $2}')

Si ce n'est pas trop hardcore pour vous, je vous suggérons de compiler à la suite de C-programme de langue:

#include <stdio.h>
#include <inttypes.h>
typedef union {
char array[sizeof(int32_t)];
int32_t val;
} int32_u;
typedef union {
char array[sizeof(uint32_t)];
uint32_t val;
} uint32_u;
typedef union {
char array[sizeof(uint64_t)];
uint64_t val;
} uint64_u;
typedef union {
char array[sizeof(int64_t)];
int64_t val;
} int64_u;
int swap(char* mem, int size) {
if (size & 1 != 0)
return -1;
int i;
for (i = 0; i < size / 2; i++) {
char tmp = mem[i];
mem[i] = mem[size - i - 1];
mem[size - i - 1] = tmp;
}
return 0;
}
int sys_big_endian() {
int x = 1;
return !(*(char*)&x);
}
int main(int argc, char** argv) {
char* file_name = NULL;
int offset = 0;
char* type = "int32";
int big_endian = 0;
int i;
for(i = 1; i < argc; i++) {
if(!strncmp("-o", argv[i], 2)) {
++i;
sscanf(argv[i], "%d", &offset);
} else if(!strncmp("-t", argv[i], 2)) {
++i;
type = argv[i];
} else if(!strncmp("-e", argv[i], 2)) {
++i;
big_endian = !strncmp("big", argv[i], 3);
} else {
file_name = argv[i];
break;
}
}
if (i < argc - 1) {
fprintf(stderr, "Ignoring extra arguments: ");
++i;
for (; i < argc; i++) {
fprintf(stderr, "%s ", argv[i]);
}
fprintf(stderr, "\n");
}
if (file_name == NULL) {
fprintf(stderr, "Syntax: readint [-o offset] [-t type] [-e endian] <filename>\n"
"Where:\n"
"  type      'uint32', 'uint64', 'int32' (default), 'int64'.\n"
"  endian    'big' or 'little' (default).\n"
"  offset    offset in a file from where the read will happen, default is 0.\n"
);
return -1;
}
FILE* fp = fopen(file_name, "rb");
if (fp == NULL) {
fprintf(stderr, "Could not open the file: %s\n", file_name);
return -1;
}
fseek(fp, offset, SEEK_SET);
if (!strncmp("uint32", type, 6)) {
uint32_u u;
fread(u.array, sizeof(u.array), 1, fp);
if (big_endian ^ sys_big_endian())
swap(u.array, sizeof(u.array));
printf("%u\n", u.val);
} else if (!strncmp("int32", type, 5)) {
int32_u u;
fread(u.array, sizeof(u.array), 1, fp);
if (big_endian ^ sys_big_endian())
swap(u.array, sizeof(u.array));
printf("%d\n", u.val);
} else if (!strncmp("uint64", type, 6)) {
uint64_u u;
fread(u.array, sizeof(u.array), 1, fp);
if (big_endian ^ sys_big_endian())
swap(u.array, sizeof(u.array));
printf("%"PRIu64"\n", u.val);
} else if (!strncmp("int64", type, 5)) {
int64_u u;
fread(u.array, sizeof(u.array), 1, fp);
if (big_endian ^ sys_big_endian())
swap(u.array, sizeof(u.array));
printf("%"PRId64"\n", u.val);
} else {
printf("Unknown type: %s\n", type);
}
fclose(fp); 
return 0;
}

Ensuite ce faire:

gcc -o readint readint.c
sudo mv readint /usr/local/bin

Vous avez maintenant un outil pratique appelée "readint" avec la syntaxe suivante:

readint [-o offset] [-t int32|uint32|int64|uint64 ] [-e little|big ] <filename>