Английская Википедия:Chsh
Шаблон:For Шаблон:Lowercase Шаблон:Infobox Software chsh (an abbreviation of "change shell") is a command on Unix-like operating systems that is used to change a login shell. Users can either supply the pathname of the shell that they wish to change to on the command line, or supply no arguments, in which case Шаблон:Mono allows the user to change the shell interactively.[1]
Usage
Шаблон:Mono is a setuid program that modifies the Шаблон:Mono file, and only allows ordinary users to modify their own login shells. The superuser can modify the shells of other users, by supplying the name of the user whose shell is to be modified as a command-line argument. For security reasons, the shells that both ordinary users and the superuser can specify are limited by the contents of the Шаблон:Mono file, with the pathname of the shell being required to be exactly as it appears in that file. (This security feature is alterable by re-compiling the source code for the command with a different configuration option, and thus is not necessarily enabled on all systems.) The superuser can, however, also modify the password file directly, setting any user's shell to any executable file on the system without reference to Шаблон:Mono and without using Шаблон:Mono.[1][2][3]
On most systems, when Шаблон:Mono is invoked without the Шаблон:Mono command-line option (to specify the name of the shell), it prompts the user to select one. On Mac OS X, if invoked without the Шаблон:Mono option, Шаблон:Mono displays a text file in the default editor (initially set to vim) allowing the user to change all of the features of their user account that they are permitted to change, the pathname of the shell being the name next to "Shell:". When the user quits vim, the changes made there are transferred to the /etc/passwd file which only root can change directly.[2][4]
Using the Шаблон:Mono option (for example: Шаблон:Code) greatly simplifies the task of changing shells.
Depending on the system, Шаблон:Mono may or may not prompt the user for a password before changing the shell, or entering interactive mode. On some systems, use of Шаблон:Mono by non-root users is disabled entirely by the sysadmin.[4]
On many Linux distributions, the Шаблон:Mono command is a PAM-aware application. As such, its behaviour can be tailored, using PAM configuration options, for individual users. For example, an Шаблон:Mono directive that specifies the Шаблон:Mono module can be used to deny Шаблон:Mono access to individual users, by specifying a file of the usernames to deny access to with the Шаблон:Mono option to that module (along with the Шаблон:Mono option).[5]
Portability
POSIX does not describe utilities such as Шаблон:Mono, which are used for modifying the user's entry in Шаблон:Mono. Most Unix-like systems provide Шаблон:Mono.[6] SVr4-based systems provided a similar capability with passwd. Two of the three remaining systems (IBM AIX[7] and HP-UX[8]) provide Шаблон:Mono in addition to Шаблон:Mono. The exception is Solaris, where non-administrators are unable to change their shell unless a network name server such as NIS or NIS+ is installed.[9][10] The obsolete[11] SGI SVr4 system IRIX64 also lacked Шаблон:Mono.
See also
References
Further reading
- Шаблон:Cite book — some examples of invoking Шаблон:Mono with the Шаблон:Mono and Шаблон:Mono options
External links
