Prints a detailed view of all arguments. When you're confused about args, substitute in `cmdinfo` for a hex dump of every arg.

cmdinfo.c

// Compile with:
//     gcc ./cmdinfo.c -lm -o cmdinfo

#include <stdio.h>  /* printf(), fprintf() */
#include <string.h> /* strcmp() */
#include <math.h> /* log10(), ceil() */

// fwd decl to cease warnings
int print_arguments(FILE* outf, int argc, char *const *argv);
int xxdline(int lineno, char* input, int inputlen, char* outbuf);
char* cleanstr(char* str);

int main(int argc, char *const *argv){
	FILE* outf = stdout;
	if (argc == 2 && ((strcmp(argv[1], "-h")==0) || (strcmp(argv[1], "--help") ==0 ))) {
		outf = stderr;
		fprintf(outf, "Usage: %s [arguments]\n\n", argv[0]);
		fprintf(outf, "Prints a detailed view of all arguments. A program for examining all\n");
		fprintf(outf, "arguments provided as 'argv'. Useful to insert into scripts for\n");
		fprintf(outf, "debugging purposes. The following is an example of the info this\n");
		fprintf(outf, "program prints, but run against your '%s' argument:\n\n", argv[1]);
		// Intentionally do not exit, we run against the 'help' flag as an example
	}
	if (argc == 0) {
		return 0;
	}
	print_arguments(outf, argc, argv);
}

// print_arguments prints each argument in argv, one after another, one per
// line, with leading text explaining what's in that argument.
int print_arguments(FILE* outf, int argc, char *const *argv) {
	int chwidth = ceil(log10(argc+1));
	fprintf(outf, "#Number of arguments: %d, width of number of args: %d\n\n", argc, chwidth);

	char fmt[30];
	snprintf(fmt, 30, "Argument #%%0%dd: %%s\n", chwidth);
	for (int i = 0; i < argc; i++) {
		fprintf(outf, fmt, i, cleanstr(argv[i]));

		int arglen = strlen(argv[i]);
		for (int k = 0; k < arglen; k = k+16) {
			char buf[70];
			int linelen = arglen - k;
			if (linelen>16) {
				linelen=16;
			}
			xxdline(k/16, argv[i] + k, linelen, buf);
			fprintf(outf, "%s\n", buf);
		}
		fprintf(outf, "\n");
	}
	return 0;
}

char chartodisp(char c) {
	if ((c > 31) && (c < 127)) {
		return c;
	}
	return '.';
}


// input is a buffer that's of inputlen in length, a maximum of 16.
// outbuf must be exactly 70 chars long
// lineno is the 0-index line that we're printing
int xxdline(int lineno, char* input, int inputlen, char* outbuf) {
	int firstbyteofline = 16*lineno;

	char buf[40];
	memset(buf, ' ', 39);
	buf[39] = '\0';
	for (int i = 0; i< inputlen; i++) {
		char byte = input[i];
		int hexbyteloc = (i*2) + (i/2);
		char b[3];
		snprintf(b, 3, "%02x", byte);
		buf[hexbyteloc+0] = b[0];
		buf[hexbyteloc+1] = b[1];
	}

	char humchars[17];
	memset(humchars, ' ', 16);
	humchars[16] = '\0';
	for (int i = 0; i< inputlen; i++) {
		char c = chartodisp(input[i]);
		humchars[i] = c;
	}

	snprintf(outbuf, 70, "%08x: %s | %s", firstbyteofline, buf, humchars);
}

char* cleanstr(char* str) {
	char* newstr = strdup(str);
	int ln = strlen(str);
	for (int i = 0; i < ln; i++) {
		newstr[i] = chartodisp(newstr[i]);
	}
	return newstr;
}