This may sound silly, but I have a file/ script that need to run and in order to do it I must change it to become executable. I would want to use either chmod a+x or chmod 755. But is there a difference between using chmod a+x and chmod 755?
这听起来很傻，但是我有一个文件/脚本需要运行，为了做到这一点，我必须将它更改为可执行文件。我想用chmod a+x或chmod 755。但是使用chmod a+x和chmod 755有区别吗?
3 个解决方案
#1
49
chmod a+x modifies the argument's mode while chmod 755 sets it. Try both variants on something that has full or no permissions and you will notice the difference.
chmod a+x修改参数的模式，而chmod 755设置。尝试两个变量都有完全或没有权限，您将注意到差异。
#2
30
Yes - different
是的,不同的
chmod a+x will add the exec bits to the file but will not touch other bits. For example file might be still unreadable to others and group.
chmod a+x将把exec位添加到文件中，但不会触及其他位。例如，文件可能仍然不能读给其他人和组。
chmod 755 will always make the file with perms 755 no matter what initial permissions were.
无论初始权限是什么，chmod 755总是会使文件具有perm755。
This may or may not matter for your script.
这可能对您的脚本很重要。
#3
19
Indeed there is.
确实有。
chmod a+x is relative to the current state and just sets the x flag. So a 640 file becomes 751 (or 750?), a 644 file becomes 755.
chmod a+x相对于当前状态，只设置x标志。所以640个文件变成751(或750?)，644个文件变成755。
chmod 755, however, sets the mask as written: rwxr-xr-x, no matter how it was before. It is equivalent to chmod u=rwx,go=rx.
然而，chmod 755却设置了这样的掩码:rwxr-xr-x，不管它以前是什么样子。它等于chmod u=rwx,go=rx。
#1
49
chmod a+x modifies the argument's mode while chmod 755 sets it. Try both variants on something that has full or no permissions and you will notice the difference.
chmod a+x修改参数的模式，而chmod 755设置。尝试两个变量都有完全或没有权限，您将注意到差异。
#2
30
Yes - different
是的,不同的
chmod a+x will add the exec bits to the file but will not touch other bits. For example file might be still unreadable to others and group.
chmod a+x将把exec位添加到文件中，但不会触及其他位。例如，文件可能仍然不能读给其他人和组。
chmod 755 will always make the file with perms 755 no matter what initial permissions were.
无论初始权限是什么，chmod 755总是会使文件具有perm755。
This may or may not matter for your script.
这可能对您的脚本很重要。
#3
19
Indeed there is.
确实有。
chmod a+x is relative to the current state and just sets the x flag. So a 640 file becomes 751 (or 750?), a 644 file becomes 755.
chmod a+x相对于当前状态，只设置x标志。所以640个文件变成751(或750?)，644个文件变成755。
chmod 755, however, sets the mask as written: rwxr-xr-x, no matter how it was before. It is equivalent to chmod u=rwx,go=rx.
然而，chmod 755却设置了这样的掩码:rwxr-xr-x，不管它以前是什么样子。它等于chmod u=rwx,go=rx。