如何解决gcc生成.o，但bash表示未知命令
编辑：我已经修复了已指出的几件事，但实际问题仍未解决。 这个bash脚本：set -vx
/usr/bin/llvm-gcc-4.2 -ansi -g -o mytest mytest.c
ls -l mytest
./mytest
file mytest
/usr/bin/llvm-gcc-4.2 -ansi -g -o mytest mytest.c
++ /usr/bin/llvm-gcc-4.2 -ansi -g -o mytest mytest.c
ls -l mytest
++ ls -l mytest
-rwxr-xr-x 1 jimslager wheel 37496 May 27 17:26 mytest
./mytest
++ ./mytest
error: unknown command ./mytest
file mytest
++ file mytest
mytest: Mach-O 64-bit executable x86_64
/* Test Exercise 5-10: Write the program myexpr,which evaluates a reverse Polish expression from the command line,where each operator or operand is a separate argument. For example,* expr 2 3 4 + *
* evaluates 2 x (3+4).
* */
#include <stdio.h>
#include <string.h>
#define MAXLINE 68
#define TABSIZE 8
#define TAB \'`\'
#define SPACE \'-\'
#define NEW \'\\\\\'
#define TRUE 1
#define FALSE 0
#define IN 1
#define OUT 0
#define FOLDLENGTH 20
#define MAXLEN 12
#define SMALLER(i,j) ((i) > (j) ? (j) : (i))
#define N(c) (c==\'\\0\' ? \'\\\\\' : c)
/* #include \"subs.c\" */
#define MAXOP 100 /* max size of operand or operator */
#define NUMBER \'0\' /* signal that a number was found */
int getop(char []);
void push(double);
double pop(void);
double top(void);
void dup(void);
void clear(void);
void stackswap(void);
double atof(char s[]);
int myisdigit(char c);
int myisspace(char c);
/* reverse Polish calculator */
int main(int argc,char *argv[])
{
int type;
double op2;
char s[MAXOP];
while (--argc>0)
while (type = getop(&(*++argv[0])))
printf(\"Just after while: type = %d,*argv[0] = %s\\n\",type,*argv);
switch (type) {
case NUMBER:
push(atof(*argv));
printf(\"NUMBER: atof(*argv[0]) = %g,atof(*argv),*argv);
break;
case \'+\':
printf(\"+ detected\\n\");
push(pop() + pop());
break;
case \'*\':
printf(\"* detected\\n\");
push(pop() * pop());
break;
case \'-\':
printf(\"- detected\\n\");
op2 = pop();
push(pop() - op2);
break;
case \'/\':
printf(\"/ detected\\n\");
op2 = pop();
if (op2 != 0.0)
push(pop() / op2);
else
printf(\"error: zero divisor\\n\");
break;
case \'%\':
printf(\"Modulo detected\\n\");
op2 = pop();
if (op2 != 0.0)
push((int) pop() % (int) op2);
else
printf(\"error: zero divisor\\n\");
break;
case \'t\':
printf(\"t detected\\n\");
printf(\"%g\\n\",top());
break;
case \'d\':
printf(\"d detected\\n\");
dup();
break;
case \'s\':
printf(\"s detected\\n\");
stackswap();
break;
case \'c\':
printf(\"c detected\\n\");
clear();
break;
case \'\\n\':
printf(\"\\\\n detected\\n\");
printf(\"\\t%.8g\\n\",pop());
break;
default:
printf(\"error: unknown command %s\\n\",*argv);
break;
}
return 0;
}
#define MAXVAL 100 /* maximum depth of val stack */
int sp = 0; /* next free stack position */
double val[MAXVAL]; /* value stack */
/* push: push f onto value stack */
void push(double f)
{
printf(\"push: Started. f = %g,sp = %d\\n\",f,sp);
if (sp < MAXVAL)
val[sp++] = f;
else
printf(\"error: stack full,can\'t push %g\\n\",f);
printf(\"push: Finished. f = %g,sp);
}
/* dup: duplicate top of stack */
void dup(void)
{
printf(\"dup: Started. top = %g,top(),sp);
push(top());
printf(\"dup: Finished. top = %g,sp);
}
/* pop: pop and return top value from stack */
double pop(void)
{
printf(\"pop: sp = %d,val[--sp] = %g\\n\",sp,val[sp-1]);
if (sp > 0)
return val[--sp];
else {
printf(\"error: stack empty\\n\");
return 0.0;
}
}
/* top: return top value from stack without changing sp */
double top(void)
{
printf(\"top: sp = %d,val[0] = %g\\n\",val[0]);
if (sp > 0)
return val[sp-1];
else {
printf(\"error: stack empty\\n\");
return 0.0;
}
}
/* stackswap: swap the top 2 values in stack */
void stackswap(void)
{
printf(\"Starting stackswap: val[sp-1] = %g,val[sp-2] = %g\\n\",val[sp-1],val[sp-2]);
double op2,op3;
op2 = pop();
op3 = pop();
push(op2);
push(op3);
printf(\"Finishing stackswap: val[sp-1] = %g,val[sp-2]);
}
/* clear: clear the stack */
void clear(void)
{
sp = 0;
}
int getch(void);
void ungetch(int);
/* getop: get next character or numeric operand */
int getop(char s[])
{
int i,c;
while ((s[0] = c = getch()) == \' \' || c == \'\\t\')
;
s[1] = \'\\0\';
if (!isdigit(c) && c != \'.\')
return c; /* not a number */
i = 0;
if (isdigit(c)) /* collect integer part */
while (isdigit(s[++i] = c = getch()))
;
if (c==\'.\') /* collect fraction part */
while (isdigit(s[++i] = c = getch())) ;
s[i] = \'\\0\';
if (c != EOF)
ungetch(c);
return NUMBER;
}
#define BUFSIZE 100
char buf[BUFSIZE]; /* buffer for ungetch */
int bufp = 0; /* next free position in buf */
int getch(void) /* get a (possibly pushed-back) character */
{
return (bufp > 0) ? buf[--bufp] : getchar();
}
void ungetch(int c) /* push character back on input */
{
if (bufp >= BUFSIZE)
printf(\"ungetch: too many characters\\n\");
else
buf[bufp++] = c;
}
/* atof: convert s to double */
double atof(char s[])
{
double val,power,epower,d;
int i,j,sign,esign=0,eval;
printf(\"atof: s = %s\\n\",s);
for (i = 0; myisspace(s[i]); i++); /* skip white space */
sign = (s[i] == \'-\') ? -1 : 1; /* Determine sign and strip it */
if (s[i] == \'+\' || s[i] == \'-\')
i++;
for (val = 0.0; myisdigit(s[i]); i++) /* Determine value before dec point */
val = 10.0 * val + (s[i] - \'0\');
if (s[i] == \'.\')
i++;
for (power = 1.0; myisdigit(s[i]); i++) { /* include value after dec */
val = 10.0 * val + (s[i] - \'0\');
power *= 10; /* power is where . goes */
}
if (s[i]==\'e\' || s[i]==\'E\') { /* Exponential form */
esign = (s[++i]==\'-\') ? -1 : 1; /* Sign of exponent */
if (s[i]==\'+\' || s[i]==\'-\')
i++;
for (epower=0.1,eval=0.0; myisdigit(s[i]); i++) { /* Determine exponent */
eval = 10*eval + (s[i]-\'0\');
epower *= 10;
}
}
d = (sign*val / power); /* Place dec point in mantissa */
if (esign!=0) { /* If exp form then adjust exponent */
for (j=1; j<=eval; j++) {
d = (esign==1 ? d*10.0 : d/10.0);
}
}
return (d);
}
/* Determine is c is a digit */
int myisdigit(char c)
{
if (c>=\'0\' && c<=\'9\')
return TRUE;
else
return FALSE;
}
/* Returns 1 if c is whitespace,0 otherwise */
int myisspace(char c)
{
return ((c==\' \' || c==\'\\n\' || c==\'\\t\') ? 1 : 0);
}
解决方法
可能应该是./test.o来运行它。通常，缺省情况下，UNIX系统的PATH中没有\“。\”（当前目录）。
同样，“。o”扩展名也会引起误解，因为这是中间目标文件的约定，而不是您在此处生成的独立可执行文件。
, 最后一行line3ѭ，一切正常。
如果仅提供文件名而不提供路径，则仅考虑搜索路径，并且在大多数情况下，您当前的工作目录不是其中的一部分（在您的示例中，肯定不是）。
,
.
$PATH
./test.o
.o
./test.o
.o
file test.o
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