User & Groups, Permissions and Printing

Transcription

1 nit 7 ser & roups, ermissions and rinting DW DW

2 opics for this nit sers and groups inux ermissions inux rinting DW DW

3 sers and roups DW DW

4 oot is the superuser which means root is the system administrator oot s home directory is located at /root ll other user home directories are located at /home DW DW

5 ser asswords ocated in /etc/passwd Consists of seven fields username password (encrypted) D (user id) D (group id) comment home directory shell DW DW

6 hadow asswords ocated in the /etc/shadow file hadow file is an encrypted version of the user password from the /etc/passwd file sers with an * in the password field are system users sers with!! n the password field must have a valid password to login the system DW DW

7 ser ccount arameters ocated in the /etc/login.defs Contains the default values to use when creating user accounts such as inimum - maximum password age inimum - - maximum values for D inimum - maximum values for D Whether or not to create a home directory, etc DW DW

8 Default nvironment Files ocated in the /etc/skel Directory hese files are copied to the user s home directory such as.bash_logout.bash_profile.bashrc.emacs.gtkrc.kde.gnome, etc. DW DW

9 useradd Creates new users and modifies existing users -d name creates the user home dir if other than the default -D creates new settings for the default account -e date sets an expiration date -g name adds user to the group -m -k skel-dir copies group template configuration and script files -n turns off creating each user as a separate group -s shell allows you to set the shell for the user DW DW

10 ser Creation rocess 1. useradd gets the default account values from /etc/login.defs 2. arses the command line to see what default values should be overwritten 3. Creates new entry in both /etc/passwd and /etc/shadow 4. Creates group entry in /etc/group 5. Creates the user home directory in the /home directory 6. Copies files from the /etc/skel directory to the new user s home directory DW DW

11 emoving sers se the userdel command se linuxconf dit the /etc/passwd file se the user manager in nome DW DW

12 Creating roups se groupadd command yntax groupadd g [D] [groupname] groupadd g 900 nt41 tored in the /etc/group file ssigned a roup D (D) Can assign users to a group using the usermod command yntax usermod [groupname] [username] usermod nt41 newguy DW DW

13 su command he substitute user allows you to run a shell as a different user without changing the directory you are in yntax su - username witches -, -l, --login makes it a login shell -m preserves environment ote: if no username is given, the root user is assumed DW DW

14 Wheel roup special group that can be used to assign administrative privileges to specific users and restrict just anyone from using the su command Create the wheel group dd users who need administrative permissions Change ownership of the /bin/su program to the wheel group chgrp wheel /bin/su chmod 4750 /bin/su DW DW

15 ser nformation id command displays user and group information yntax id or id username (no argument displays current user) finger command displays detailed information yntax finger or finger username who or who am i displays the users currently logged in yntax who argument or who am i DW DW

16 Virtual erminals ach login shell is identified as a different device by the system and is treated as a virtual terminal se alt+f1 to view the first virtual terminal, lt+f2, etc to view each succeeding terminal DW DW

17 Host ames very machine has a FQD (fully Qualified Domain ame) that consist of the hostname plus the domain name he default hostname is localhost he default domain name is localdomain herefore the default FQD is localhost.localdomain DW DW

18 ermissions DW DW

19 inux File ermissions efers to the type of access that a user has to a file or directory here are three file permissions ead (r) read a file Write (w) allows user to write to, add, or change files xecute (x) allows user to execute programs DW DW

20 ermission ssignment ser (u) means the owner of the file roup (g) means a group of users that the owner belongs to ther (o) means everyone else who are not the owner or a member of the group assigned permission to this object DW DW

21 File ermissions umerical method ead = 4 Write = 2 xecute = 1 o can use the following syntax chmod 74- means user rwxr----- DW DW

22 File ermissions Components ser D (D)- user identification assigned by the administrator to track user actions roup D (D) - group identification used to identify groups the user belongs to ticky bit - prevents users from removing files from public directories that they don t own. DW DW

23 ermissions File permissions Directory permissions r = read r = list contents w = write w = add/delete files x = execute x = cd to directory - = permission denied - = permission denied DW DW

24 ine permission bits are associated with each file and directory owner group other s rights rights rights xample File ermissions -rwxrwxr-- 1 myid Feb 02 20:36 grades.nd14 DW DW

25 File Directory Default ermissions rw-r--r rwxr-xr-x DW DW

26 he ticky Bit f a directory is writable and has the sticky bit set, files within that directory can be deleted or renamed f the user owns the file he user owns the directory he file is writable by the user he user is root DW DW

27 File ermissions Commands id command lists user id and group id chmod command changes access rights chown command changes ownership chgrp command changes group DW DW

28 umask command umask allows you to change the default file and directory permissions. fter changing with umask, all new files and directories will have the new default permissions he umask command has no effect on existing files DW DW

29 etting ermissions raphically se file manager ight click and open properties Can set permissions by checking proper box in the proper column Can also change the owner and the group DW DW

30 rinting DW DW

31 inux rinting rchitecture he lpr command prepares files to be sent to the printer rint job a file submitted for printing via the lpr command rint Filter a script used by the lpr program to prepare files to be sent to a printer DW DW

32 inux rinting rchitecture dministrative utilities that are programs used by the system administrator to manage Files that have been printed or are in the process of being printed he printer definition file (printcap) he status of each printer DW DW

33 inux rinting rchitecture Block pecial File refers to a physical device that transfers data in blocks of characters, such as a parallel port or hard disk storage. ormally located in /dev Character pecial File refers to a physical device such as a serial port that transfers data in single characters DW DW

34 ser prints a document cupsd.conf File rint rocess rint Filter formats the document cupsd sends print job to print device rint job created Job spooled to print queue (rint pool Directory) rint device creates a hard copy of the document DW DW

35 oad Balancing Cupsd daemon load balances by default if a single queue is connected to several physical print devices he term printer actually refers to the print queue rather than the physical print device his is similar to printer pooling in windows 2008 DW DW

36 rinter Queues everal printer queues can all point to the same physical print device llows a method of directing jobs requiring different forms to be sent to the same print device r segregating different types of jobs lpstat checks the state of the queue cancel cancel a job DW DW

37 he ole of rint Filters inux uses special programs that prepare data for printing ou have complete control over the operation of these programs DW DW

38 Driver oftware program that provides abstract services for a hardware component such as opening files or reading character input inux drivers are stored in a ppdfile DW DW

39 rinter anguages age Description anguage special set of codes that determine graphic elements, text font, and everything else about what appears on the page ost widely used are ostscript developed by dobe rinter Control anguage C developed by Hewlett-ackard DW DW

40 rint Filter script that contains instructions for formatting all documents for a specific printer using the page description language that the printer queue requires sed by the lpr program to prepare files to be sent to a physical printer arely as powerful as a driver because it provides no access to the advanced features of the printer agic Filter automatically processes a file into the correct output format based on the file's type DW DW

41 rinter Filter rograms wo common print filters _gshost cript _enscript ormally stored in the usr/share/zsh/4.3.10/functions different filter is defined for each print queue DW DW

42 rint olicies rinter olicy is a brief document that describes how print resources can be used and how the management of the printers will be conducted within an organization ddresses who can print, where, when, etc. ets up maintenance schedules ssigns responsibility to re-supply the printers DW DW

43 cupsd.conf ntry he printer definition file used by the inux printing system pecifies how and where files to be printed are stored and processed by lpr and cupsd Can be edited in any test editor or by using one of the graphical utilities provided with the inux distribution eneral format consists of a printer name, followed by a series of two-character option codes that apply to the printer with the option separated by two colons DW DW

44 sing the C tility 1. he inux printer control utility that lets you control the actions of the cupsd daemon specify how print jobs are accepted and processed 2. rovides functionality that is not available with most graphical utilities such as prevent any jobs from entering a print queue, cancel a print job while it is being printed, pause the print queue or check the status of all printers DW DW

45 sing the C tility ou can include an lpc command as a parameter on the command line (lpc status) or you can use lpc in an interactive mode in which you can enter multiple commands he default printer is the first printer listed in the cups file arameter all can be used to affect all printers or a name to effect only specific printers DW DW

46 rinter ptions ocal rinter attached to local machine emote remote server that uses the lpd daemon to print users jobs B/Windows 95/ rinter B does not use lpd daemon etware rinter (C) connected to a etware server on the network and uses the C protocol DW DW

47 rinter ool llows you to automatically create complex print filters for many popular printers with the Configure Filter dialog box he tool automatically updates the cups file reducing the chance of making typing or syntax errors Don t need to restart your cupsd daemon but it is usually a good idea to do it DW DW

48 How lpr elects the rinter 1. f the option is used with the lpr command, the job is sent to that printer 2. f the option is not used and an environmental variable exists for the user printing the file, the job is sent to the printer listed in the printer variable 3. f neither is present, then the printer named in the default_printer line in lpd.conf is used 4. therwise, the first printer in the printcap file is used DW DW

49 inux vs icrosoft rinting inux printing provides very few options rimarily allows direct printing with the lpr command or another command such as enscript and the choice of the selection or the entire document pplications can provide further options for printing but it is still limited compared to what windows users are accustomed to DW DW

50 anaging rinting etting up and enabling the printer Keeping printers stocked with paper, toner, ribbons, ink Clearing paper jams Keeping the printer online racking print jobs in the print queues DW DW

51 racking rint Jobs inux includes both command line and graphical utilities s usual there are some tasks that can only be done at the command line he lpq utility provides status, owner, class (priority), job number, file size and the time the print job was submitted DW DW

52 lpq ptions -s displays a shorter format Can add a job D to the lpq command - to view jobs in a specific print queue se lprm job_id to delete a print job from the queue dash can delete all of the jobs in a queue lprm printer_name - DW DW

53 rint ccounting eports se the pac (print accounting) command to display reports based on the accounting data f you use the af option in the printcap file, each print job creates a print accounting entry in the file specified by the af option -m combines all of the user s job from all servers into a single listing se the user s D to see all accounting information for a single user DW DW

54 raphical tilities he klpq program part of the KD desktop Can remove jobs Can select the print queue to view When queuing box is checked new jobs can be sent to the queue Checking printing allows jobs to be sent to lpd daemon DW DW

55 emote rinting ittle configuration required to connect the lpd daemon on one inux box to the lpd daemon on another box and transfer a print job for remote printing systems useing the lpd daemon can accept print jobs from a inux system and vice versa eeds the print queue name, hostname or ip address of the remote computer dd these to printcap to the rp and rm options or define a new print queue for the remote printer DW DW

56 rocessing a emote rint Job he print job is not passed through a filter until it reaches the lpd program on the remote system nce a print jon has been submitted to a remote system, the local lpd daemon has nothing to do with it ust have a user account on the remote system o restrict user from using a remote printer default settings must be changed in the printcap or lpd.perms file DW DW

57 rinting o etwork rinters Bounce Queue (bq) is an option code in the printcap file that causes print jobs to be processed by the print filter before being sent to a remote printer Designed especially for printers connected directly to the network Bq lexmark DW DW

58 rinting o on-inux ystems special printer daemon can be used by other operating systems along with F to enable printing he amba uite of pplications must be installed and configured to print to a printer connected to a windows based computer rovides B protocol support to inux so that files and printers can be shared between inux and Windows systems DW DW

59 ab 7 dd users at both the command line and the dd the users to a group et the users password Configure a dummy printer Configure a network printer DW DW