Why doesn’t an import in an exec in a function work?
How about this: def test(): exec (code, globals()) f()
exec
Is it possible to execute a string in MySQL?
I think you’re looking for something like this: SET @queryString = ( SELECT CONCAT(‘INSERT INTO user_group (`group_id`,`user_id`) VALUES ‘, www.vals) as res FROM ( SELECT GROUP_CONCAT(qwe.asd SEPARATOR ‘,’) as vals FROM ( SELECT CONCAT(‘(59,’, user_id, ‘)’) as asd FROM access WHERE residency = 9 ) as qwe ) as www ); PREPARE stmt FROM @queryString; … Read more
Faster forking of large processes on Linux?
On Linux, you can use posix_spawn(2) with the POSIX_SPAWN_USEVFORK flag to avoid the overhead of copying page tables when forking from a large process. See Minimizing Memory Usage for Creating Application Subprocesses for a good summary of posix_spawn(2), its advantages and some examples. To take advantage of vfork(2), make sure you #define _GNU_SOURCE before #include … Read more
Is it possible to signal handler to survive after “exec”?
No. From the man pages: execve() does not return on success, and the text, data, bss, and stack of the calling process are overwritten by that of the program loaded. The program invoked inherits the calling process’s PID, and any open file descriptors that are not set to close on exec. Signals pending on the … Read more
How to use a variable to indicate a file descriptor in bash?
The accepted answer is correct, but as of bash 4.1, you can use automatic file descriptor allocation, and in that case you don’t need eval: file=a exec {id}<>”$file” Then you can use it like this: echo test >&${id} or: fsck -v -f -C ${id} /dev/something
Setting variables with executing a command with exec
You need to use env to specify the environment variable: exec env MY_VARIABLE=my_value ./my_script.sh If you want your script to start with an empty environment or with only the specified variables, use the -i option. From man env: env – run a program in a modified environment
What are shell form and exec form?
The docker shell syntax (which is just a string as the RUN, ENTRYPOINT, and CMD) will run that string as the parameter to /bin/sh -c. This gives you a shell to expand variables, sub commands, piping output, chaining commands together, and other shell conveniences. RUN ls * | grep $trigger_filename || echo file missing && … Read more
How do I execute a Shell built-in command with a C function?
If you just want to execute the shell command in your c program, you could use, #include <stdlib.h> int system(const char *command); In your case, 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 … Read more