Running Commands with root Privileges 431 in .NET Encoder EAN/UCC-13 in .NET Running Commands with root Privileges 431

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Running Commands with root Privileges 431 generate, create ean13 none in .net projects Visual Studio 2010 password, tu .net framework EAN/UCC-13 rning this flag on may confuse users. Do not turn on this flag if you have not unlocked the root account (page 431), as you will not be able to use sudo.

To fix this problem, bring the system up in recovery mode (page 445) and turn off (remove) this flag. The default is off, causing sudo to prompt for the password of the user running sudo. See the preceding tip.

. shell_noargs Causes sudo, when called without any arguments, to spawn a root shell without changing the environment. The default is off. This option is the same as the sudo s.

option. timestamp_timeout=mins The mins is EAN 13 for .NET the number of minutes that the sudo timestamp (page 423) is valid. The default is 15; set mins to 1 to cause the timestamp to be valid forever.

. tty_tickets Causes sudo to authenticate users on a per-tty basis, not a per-user basis. The default is on. umask=val Th e val is the umask (page 459) that sudo uses to run the command that the user specifies. Set val to 0777 to preserve the user s umask value. The default is 0022.

. Unlocking th EAN 13 for .NET e root Account (Assigning a Password to root). Except for a few instances, there is no need to unlock the root account on an Ubuntu system; in fact, Ubuntu suggests that you do not do so. The following command unlocks the root account by assigning a password to it:. $ sudo passw EAN-13 for .NET d root Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully Relocking the root account. If you decid e you want to lock the root account after unlocking it, give the command sudo passwd l root. You can unlock it again with the preceding command..

su: Gives You Another User s Privileges To use su to gain root privileges, you must unlock the root account (as discussed in the preceding section). The su (substitute user) utility can spawn a shell or execute a program with the identity and privileges of a specified user. Follow su on the command line with the name of a user; if you are working with root privileges or if you know the user s password, you will then take on the identity of that user.

When you give an su command without an argument, su defaults to spawning a shell with root privileges (you have to know the root password). When you give an su command to work as root, su spawns a new shell, which displays the # prompt. You can return to your normal status (and your former shell and prompt) by terminating this shell: Press CONTROL-D or give an exit command.

Giving an su command by itself changes your user and group IDs but makes minimal changes to the environment. For example, PATH has the same value as it did before. 432 11 System Administration: Core Concepts you gave the su command. When you give the command su (you can use l or login in place of the hyphen), you get a root login shell: It is as though you logged in as root. Not only do the shell s user and group IDs match those of root, but the environment is identical to that of root.

The login shell executes the appropriate startup files (page 293) before displaying a prompt. The id utility displays the changes in your user and group IDs and in the groups you are associated with:. $ id uid=100 .net framework GTIN-13 2(sam) gid=1002(sam) groups=117(admin),1002(sam) $ su Password: # id uid=0(root) gid=0(root) groups=0(root). You can use su with the c option to run a command line with root privileges, returning to the original shell when the command finishes executing. The following example first shows that a user is not permitted to kill (page 455) a process. With the use of su c and the root password, however, the user is permitted to kill the process.

The quotation marks are necessary because su c takes its command as a single argument..
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