Redhat RHEL System Administration Exam Solution Manual Already Passed

Redhat RHEL System Administration Exam Solution Manual Already Passed Cockpit - Answers a system administration tool that provides a user interface for monitoring and administering servers through a web browser. The subscription service - Answers provides a mechanism to handle Red Hat software inventory and allows you to install additional software or update already installed programs to newer versions using the yum package manager. recommended way to register your system and attach subscriptions In Red Hat Enterprise Linux 7 - Answers use Red Hat Subscription Management. 1. stdin 0 - Answers Standard input to the program. 2. stdout 1 - Answers Standard output from the program. 3. stderr 2 - Answers Standard error output from the program. redirect std output to filename - Answers > filename or 1> filename append std out to filename - Answers >> filename append std out and std err to filename - Answers >> filename 2>&1 or 1>> filename 2>&1 take input from filename - Answers < filename or 0 < filename redirect std error to filename - Answers 2> filename redirect std out and std error to filename - Answers 1> filename 2>&1 or > filename 2>&1 This command redirects the normal output (contents of goodfile) to the file output and sends any errors (about badfile not existing for example) to the file errors - Answers # cat goodfile badfile 1> output 2> errors This command redirects the input for the mail command to come from file textfile and any errors are redirected to the file errors - Answers # mail user_id < textfile 2> errors This command redirects the normal output to the file abc. The construct "2>&1" says "send error output to the same place we directed normal output" - Answers # find / -name xyz -print 1> abc 2>&1 any output of the grep command is sent to the file out and any errors are sent to the file err - Answers # ( grep Bob filex > out ) 2> err Use the useradd command to add new user - Answers # useradd [options] [username] # useradd -D - Answers GROUP=100 HOME=/home INACTIVE=-1 EXPIRE= SHELL=/bin/bash SKEL=/etc/skel CREATE_MAIL_SPOOL=yes For example - Answers to change the default user shell for new user to /bin/ksh :,# useradd -D -s /bin/ksh To simple add a user with all default options : - Answers # useradd user01 To add user with uid 1099 - Answers comment "new user" and default shell as /bin/ksh : , # useradd -u 1099 -c "new user" -s /bin/ksh user01 Check new user's entry in /etc/passwd file : - Answers grep user01 /etc/passwd To modify existing user (e.g. changing the comment) : - Answers # usermod -c "modified user" user01 To assign the password to new user: - Answers # passwd user01 View the /etc/shadow file : - Answers # grep user01 /etc/shadow user01:$6$dox84xyJ$89DdMcxSlI9OHxUCyY1ryaFsmG6MSEwbmSbZXJoFY.tHgdEEeQQgQjDV0dD8jEiHusrUjj3p8gtMTKR4sXXN5.:17058:0:45:7::: You can create a user with nologin shell for running services such as SMTP and FTP etc. A user without a login shell can not login to a system and therefore cannot run any command on the system interactively on the system. Processes can run as that users however. To add new user "test" with shell nologin : - Answers # useradd -s /sbin/nologin test Make sure the nologin shell is present in the /etc/shells file : - Answers # cat /etc/shells create softlink - Answers # ln -s file link # ls -l -rw-r--r-- 1 root root 0 Sep 19 14:41 link lrwxrwxrwx 1 root root 5 Sep 19 15:41 link -> file - Answers The "l" in the "ls -l" command output above indicates that the file is a soft link. 2. The size of the soft link created in the example above is the no of characters in the pathname (file) which is 5 (it can be absolute or relative). 3. If you delete the original file (file) the soft link render as useless. 4. Soft links can reside on different file systems. 5. You can create soft links to directories also. create hard link - Answers # ln file1 file2 # ls -li 1282 -rw-r--r-- 2 root 0 root 0 Sep 23 13:19 file1 1282 -rw-r--r-- 2 root 0 root 0 Sep 23 13:19 file2 # find . -inum 1282 ./file1 ./file2 - Answers 2. The link count increases by one. everytime you create a new hard link to the file as shown above. 3. Even if you delete any one of the file. it has no effect on the other file. Only the link count decrements 4. Hard links can not cross the file system. 5. You can not create hard links to directories. display the current date and time - Answers #date display the current date and time verbosely universal time time zone - Answers #timedatectl To display all network connections - Answers ~]# nmcli con show To display the active network connection - Answers ~]# nmcli con show --active To display all network configuration settings of a particular connection - Answers ~]# nmcli con show "con-name" GUI Web base to monitor all things of RHEL - Answers Cockpit various types of network interfaces - Answers bond, team, bridge, VLAN