C语言 如何使用 C 函数执行 Shell 内置命令？
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How do I execute a Shell built-in command with a C function?
提问by user2851770
I would like to execute the Linux command "pwd" through a C language function like execv().
我想通过像execv()这样的C语言函数来执行Linux命令“pwd”。
The issue is that there isn't an executable file called "pwd" and I'm unable to execute "echo $PWD", since echo is also a built-in command with no executable to be found.
问题是没有名为“pwd”的可执行文件，我无法执行“echo $PWD”，因为 echo 也是一个内置命令，找不到可执行文件。
采纳答案by Kerrek SB
You should execute sh -c echo $PWD; generally sh -cwill execute shell commands.
你应该执行sh -c echo $PWD; 一般sh -c会执行shell命令。
(In fact, system(foo)is defined as execl("sh", "sh", "-c", foo, NULL)and thus works for shell built-ins.)
（实际上，system(foo)被定义为execl("sh", "sh", "-c", foo, NULL)，因此适用于 shell 内置函数。）
If you just want the value of PWD, use getenv, though.
但是，如果您只想要 的值PWD，请使用getenv。
回答by smRaj
If you just want to execute the shell command in your c program, you could use,
如果你只想在你的 c 程序中执行 shell 命令，你可以使用，
#include <stdlib.h>
int system(const char *command);
In your case,
在你的情况下，
system("pwd");
The issue is that there isn't an executable file called "pwd" and I'm unable to execute "echo $PWD", since echo is also a built-in command with no executable to be found.
问题是没有名为“pwd”的可执行文件，我无法执行“echo $PWD”，因为 echo 也是一个内置命令，找不到可执行文件。
What do you mean by this? You should be able to find the mentioned packages in /bin/
你这是什么意思？您应该能够在/bin/ 中找到提到的包
sudo find / -executable -name pwd
sudo find / -executable -name echo
回答by PhillipD
You can use the excecl command
您可以使用 execl 命令
int execl(const char *path, const char *arg, ...);
Like shown here
就像这里显示的一样
#include <stdio.h>
#include <unistd.h>
#include <dirent.h>
int main (void) {
return execl ("/bin/pwd", "pwd", NULL);
}
The second argument will be the name of the process as it will appear in the process table.
第二个参数将是进程的名称，因为它将出现在进程表中。
Alternatively, you can use the getcwd() function to get the current working directory:
或者，您可以使用 getcwd() 函数获取当前工作目录：
#include <stdio.h>
#include <unistd.h>
#include <dirent.h>
#define MAX 255
int main (void) {
char wd[MAX];
wd[MAX-1] = '##代码##';
if(getcwd(wd, MAX-1) == NULL) {
printf ("Can not get current working directory\n");
}
else {
printf("%s\n", wd);
}
return 0;
}
