RHCSA EX200

Objectives
RHCSA EX200 - Understand and use essential tools

RHCSA EX200 - Accessing linux systems LAB
RHCSA EX200 - VIM Survival kit LAB
RHCSA EX200 - Managing Files LAB
RHCSA EX200 - Input/Output Redirection LAB

Objectives

EX200 Objectives

Study points for the exam

RHCSA exam candidates should be able to accomplish the tasks below without assistance. These have been grouped into several categories.

Understand and use essential tools

Access a shell prompt and issue commands with correct syntax
Use input-output redirection (>, >>, |, 2>, etc.)
Use grep and regular expressions to analyze text
Access remote systems using SSH
Log in and switch users in multiuser targets
Archive, compress, unpack, and uncompress files using tar, gzip, and bzip2
Create and edit text files
Create, delete, copy, and move files and directories
Create hard and soft links
List, set, and change standard ugo/rwx permissions
Locate, read, and use system documentation including man, info, and files in /usr/share/doc

Create simple shell scripts

Conditionally execute code (use of: if, test, [], etc.)
Use Looping constructs (for, etc.) to process file, command line input
Process script inputs ($1, $2, etc.)
Processing output of shell commands within a script

Operate running systems

Boot, reboot, and shut down a system normally
Boot systems into different targets manually
Interrupt the boot process in order to gain access to a system
Identify CPU/memory intensive processes and kill processes
Adjust process scheduling
Manage tuning profiles
Locate and interpret system log files and journals
Preserve system journals
Start, stop, and check the status of network services
Securely transfer files between systems

Configure local storage

List, create, delete partitions on MBR and GPT disks
Create and remove physical volumes
Assign physical volumes to volume groups
Create and delete logical volumes
Configure systems to mount file systems at boot by universally unique ID (UUID) or label
Add new partitions and logical volumes, and swap to a system non-destructively

Create and configure file systems

Create, mount, unmount, and use vfat, ext4, and xfs file systems
Mount and unmount network file systems using NFS
Configure autofs
Extend existing logical volumes
Create and configure set-GID directories for collaboration
Diagnose and correct file permission problems

Deploy, configure, and maintain systems

Schedule tasks using at and cron
Start and stop services and configure services to start automatically at boot
Configure systems to boot into a specific target automatically
Configure time service clients
Install and update software packages from Red Hat Network, a remote repository, or from the local file system
Modify the system bootloader

Manage basic networking

Configure IPv4 and IPv6 addresses
Configure hostname resolution
Configure network services to start automatically at boot
Restrict network access using firewall-cmd/firewall

Manage users and groups

Create, delete, and modify local user accounts
Change passwords and adjust password aging for local user accounts
Create, delete, and modify local groups and group memberships
Configure superuser access

Manage security

Configure firewall settings using firewall-cmd/firewalld
Manage default file permissions
Configure key-based authentication for SSH
Set enforcing and permissive modes for SELinux
List and identify SELinux file and process context
Restore default file contexts
Manage SELinux port labels
Use boolean settings to modify system SELinux settings
Diagnose and address routine SELinux policy violations

Manage containers

Find and retrieve container images from a remote registry
Inspect container images
Perform container management using commands such as podman and skopeo
Build a container from a Containerfile
Perform basic container management such as running, starting, stopping, and listing running containers
Run a service inside a container
Configure a container to start automatically as a systemd service
Attach persistent storage to a container

RHCSA EX200 - Understand and use essential tools

RHCSA EX200 - Accessing linux systems LAB

Log in and switch users in multiuser targets
Access remote systems using SSH
Configure Key-based authentication for SSH
Securely transfer files between systems

csr@MainPC:~/Downloads$ ssh cloud_user@3.80.189.75
The authenticity of host '3.80.189.75 (3.80.189.75)' can't be established.
ED25519 key fingerprint is SHA256:4nFxuEkL7XMM8ehB0hYTUHPRJTYV0O8iyC8MsidjbUs.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '3.80.189.75' (ED25519) to the list of known hosts.
(cloud_user@3.80.189.75) Password: 
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
cloud_user@server1: ~ $ whoami ; groups
cloud_user
cloud_user wheel sysadmins
cloud_user@server1: ~ $ id
uid=1001(cloud_user) gid=1001(cloud_user) groups=1001(cloud_user),10(wheel),49999(sysadmins) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
cloud_user@server1: ~ $

This will show what happens and what files are sourced or executed when using different types of privilege elevations

cloud_user@server1: ~ $ sudo -i
[sudo] password for cloud_user: 
root@server1: ~ # echo export SOURCED1=.bash_profile >> ~/.bash_profile ; echo 'echo $SOURCED1' >> ~/.bash_profile
root@server1: ~ # grep SOURCED .bash_profile
export SOURCED1=.bash_profile
echo $SOURCED1
root@server1: ~ # echo export SOURCED2=.bashrc >> ~/.bashrc ; echo 'echo $SOURCED2' >> ~/.bashrc
root@server1: ~ # grep SOURCED .bashrc
export SOURCED2=.bashrc
echo $SOURCED2

cloud_user@server1: ~ $ sudo -k   ##  When used without a command, invalidates the user's cached credentials for the current session.  The next time sudo is run in the session, a password must be entered if the security policy requires authentication
cloud_user@server1: ~ $ sudo -i echo
[sudo] password for cloud_user: 
.bashrc
.bash_profile

cloud_user@server1: ~ $ sudo -i passwd root
[sudo] password for cloud_user: 
.bashrc
.bash_profile
Changing password for user root.
New password: 
Retype new password: 
passwd: all authentication tokens updated successfully.
cloud_user@server1: ~ $ su -c 'echo $PATH'
Password: 
/home/cloud_user/.local/bin:/home/cloud_user/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin
cloud_user@server1: ~ $ su - -c 'echo $PATH'
Password: 
.bashrc
.bash_profile
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
cloud_user@server1: ~ $

sudo = cloud_user

sudo -i = root user

su = cloud_user

su - = root user

Task 2 - access remote systems using ssh

Ssh to second server

cloud_user@server1: ~ $ ssh cloud_user@10.0.1.197
The authenticity of host '10.0.1.197 (10.0.1.197)' can't be established.
ECDSA key fingerprint is SHA256:FplhCnLMLm5YPqa00ssQlH/FEVGrxMaNkThmr4r8AaI.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.0.1.197' (ECDSA) to the list of known hosts.
Password: 
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
cloud_user@server2: ~ $

Retrieving information from remote server and creating a file to input data

cloud_user@server1: ~ $ ssh -t cloud_user@10.0.1.197 df -hT >> server_health.txt
Password: 
Connection to 10.0.1.197 closed.
cloud_user@server1: ~ $ ls
audit  build  init_pass  mariadb_repo_setup  Public  server_health.txt  Templates  wget-1.19.5-8.el8_1.1.x86_64.rpm
cloud_user@server1: ~ $ cat server_health.txt 
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
tmpfs          tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M  1.9G   1% /run
tmpfs          tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G  6.7G  67% /
tmpfs          tmpfs     373M     0  373M   0% /run/user/1001
cloud_user@server1: ~ $ ssh -t cloud_user@10.0.1.197 df free >> server_health.txt
Password: 
Connection to 10.0.1.197 closed.
cloud_user@server1: ~ $ cat server_health.txt 
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
tmpfs          tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M  1.9G   1% /run
tmpfs          tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G  6.7G  67% /
tmpfs          tmpfs     373M     0  373M   0% /run/user/1001
df: free: No such file or directory
cloud_user@server1: ~ $ free
              total        used        free      shared  buff/cache   available
Mem:        3818520      279104     2419652       18768     1119764     3297500
Swap:       8388604           0     8388604
cloud_user@server1: ~ $ ssh cloud_user@10.0.1.197
Password: 
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
Last login: Wed Apr 10 18:37:25 2024 from 10.0.1.151
cloud_user@server2: ~ $ free
              total        used        free      shared  buff/cache   available
Mem:        3818520      241588     2697600       18764      879332     3336480
Swap:       8388604           0     8388604
cloud_user@server2: ~ $ exit
logout
Connection to 10.0.1.197 closed.
cloud_user@server1: ~ $ ssh -t cloud_user@10.0.1.197 free >> server_health.txt
Password: 
Connection to 10.0.1.197 closed.
cloud_user@server1: ~ $ cat server_health.txt 
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
tmpfs          tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M  1.9G   1% /run
tmpfs          tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G  6.7G  67% /
tmpfs          tmpfs     373M     0  373M   0% /run/user/1001
df: free: No such file or directory
              total        used        free      shared  buff/cache   available
Mem:        3818520      239348     2699840       18692      879332     3338776
Swap:       8388604           0     8388604

Task 3 - creating a keygen to ssh to remote server

cloud_user@server1: ~ $ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/cloud_user/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/cloud_user/.ssh/id_rsa.
Your public key has been saved in /home/cloud_user/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:Ag8dXpCf+hWNs+ftc4ItGtOET3s3vd6UKPAWwJCdlbg cloud_user@server1
The key's randomart image is:
+---[RSA 3072]----+
|      o++ +..    |
|     o.+o+ .     |
|    o o. +.o     |
|     +  oE=..    |
|      o.S..=o    |
|      ..  ==o.. o|
|       . .o*+=.o+|
|        . .o=.=o=|
|          .. oo*.|
+----[SHA256]-----+
cloud_user@server1: ~ $ ssh-copy-id 10.0.1.197
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/cloud_user/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
Password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '10.0.1.197'"
and check to make sure that only the key(s) you wanted were added.


cloud_user@server1: ~ $ ssh cloud_user@10.0.1.197
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
Last login: Wed Apr 10 18:38:22 2024 from 10.0.1.151
cloud_user@server2: ~ $

eval used on a Unix or Linux system to execute the arguments as a shell command. The eval command is helpful when you want to execute a Unix or Linux command that has been saved in a variable

ssh-agent is a background program that handles passwords for SSH private keys. The ssh-add command prompts the user for a private key password and adds it to the list maintained by ssh-agent. Once you add a password to ssh-agent, you will not be prompted for it when using SSH or scp to connect to hosts with your public key.

cloud_user@server1: ~ $ eval $(ssh-agent -s)
Agent pid 3231
cloud_user@server1: ~ $ ssh-add
Identity added: /home/cloud_user/.ssh/id_rsa (cloud_user@server1)
cloud_user@server1: ~ $ ssh cloud_user@10.0.1.197
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
Last login: Wed Apr 10 18:41:49 2024 from 10.0.1.151
cloud_user@server2: ~ $

RHCSA EX200 - Understand and use essential tools

RHCSA EX200 - VIM Survival kit LAB

Creating, opening, and exiting a file
Making simple change to a file
Changing a system file
Simple navigation
Inserting, Copying and Deleting
Undoing and redoing
Saving and or exiting
Resources for getting help

1. - Creating opening and exiting a file.

Open a new file typing vim on shell

enter I to insert text, escape to go back to navigation mode then :w name to save the file name

now if we try to edit a system file for example vim /etc/hosts we can look at the bottom this file is readonly

to exit a file without making changes you need to exit by hitting escape key then type q! this will exit and ignore any changes

2- Making simple changes to a file

Copy a random file to make changes, we choose help.txt from vim

cloud_user@ip-10-0-1-10:~$ cp /usr/share/vim/vim80/doc/help.txt ~/vimhelp.txt
cloud_user@ip-10-0-1-10:~$ ls
myfirstnovel.txt  vimhelp.txt
cloud_user@ip-10-0-1-10:~$

vim vimhelp.txt

let s modify the VIM main help file

3.- Changing a system file

sudo -i vim /etc/hosts (will allow us to run the command as root.

add snowblower to the localhost

cloud_user@ip-10-0-1-10:~$ sudo -i vim /etc/hosts
cloud_user@ip-10-0-1-10:~$ grep snowblower /etc/hosts
127.0.0.1 localhost snowblower
cloud_user@ip-10-0-1-10:~$ ping -c 4 snowblower
PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.017 ms
64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl=64 time=0.035 ms
64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl=64 time=0.029 ms
64 bytes from localhost (127.0.0.1): icmp_seq=4 ttl=64 time=0.029 ms

--- localhost ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3055ms
rtt min/avg/max/mdev = 0.017/0.027/0.035/0.008 ms

4.- Simple Navigation

press w will take you forward one word, press b will take you backwards one word

now type / to search mode, search for Vim and hit enter it will take you to the first word that matches (capital wise) press n to go to the next one or shift n to go backwards.

5. - Inserting copying and deleting

o = insert a line below the cursor

dd = deletes a line

VA]1%Ex^

RHCSA EX200 - Understand and use essential tools

RHCSA EX200 - Managing Files LAB

creating a tar from /usr/share/doc directory

[csr@rhel-lab1 ~]$ du -sh /usr/share/doc
63M     /usr/share/doc
[csr@rhel-lab1 ~]$ tar -cf documentation.tar /usr/share/doc
tar: Removing leading `/' from member names
[csr@rhel-lab1 ~]$ ls
2  archives  documentation.tar  Desktop  Documents  Downloads  Music  output  Pictures  Public  Templates  Videos
[csr@rhel-lab1 ~]$ ls -l
total 59748
-rw-r--r--. 1 csr csr     1328 Apr 11 18:55 2
drwxr-xr-x. 2 csr csr       26 Apr  9 18:32 archives
-rw-r--r--. 1 csr csr 61173760 Apr 15 18:33 documentation.tar
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Desktop
drwxr-xr-x. 2 csr csr       72 Apr 11 18:04 Documents
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Downloads
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Music
-rw-r--r--. 1 csr csr        6 Apr 11 17:56 output
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Pictures
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Public
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Templates
drwxr-xr-x. 2 csr csr        6 Apr 10 12:03 Videos
[csr@rhel-lab1 ~]$ du -sh *.tar
59M     ddocumentation.tar

listing content of a tar file - tar-tvf filename (t list the content, -v verbose, -f use file archive)

[csr@rhel-lab1 ~]$ tar -tvf documentation.tar | more
drwxr-xr-x root/root         0 2024-04-09 17:31 usr/share/doc/
drwxr-xr-x root/root         0 2024-04-08 14:55 usr/share/doc/hwdata/
-rw-r--r-- root/root       175 2023-08-21 01:22 usr/share/doc/hwdata/LICENSE
drwxr-xr-x root/root         0 2024-04-08 14:55 usr/share/doc/xkeyboard-config/
-rw-r--r-- root/root       510 2021-06-08 15:20 usr/share/doc/xkeyboard-config/AUTHORS
-rw-r--r-- root/root      9244 2021-06-08 15:20 usr/share/doc/xkeyboard-config/COPYING
-rw-r--r-- root/root       861 2021-06-08 15:20 usr/share/doc/xkeyboard-config/HOWTO.testing
-rw-r--r-- root/root      2303 2021-06-08 15:20 usr/share/doc/xkeyboard-config/HOWTO.transition
-rw-r--r-- root/root      5108 2021-06-08 15:20 usr/share/doc/xkeyboard-config/NEWS
-rw-r--r-- root/root      1627 2021-06-08 15:20 usr/share/doc/xkeyboard-config/README
-rw-r--r-- root/root      7515 2021-06-08 15:20 usr/share/doc/xkeyboard-config/README.config
-rw-r--r-- root/root     23948 2021-06-08 15:20 usr/share/doc/xkeyboard-config/README.enhancing
-rw-r--r-- root/root      1882 2021-06-08 15:20 usr/share/doc/xkeyboard-config/README.symbols

create the same but compressed using gz

[csr@rhel-lab1 ~]$ tar -czvf documentation.tar.gz /usr/share/doc | more
tar: Removing leading `/' from member names
/usr/share/doc/
/usr/share/doc/hwdata/
/usr/share/doc/hwdata/LICENSE
/usr/share/doc/xkeyboard-config/
/usr/share/doc/xkeyboard-config/AUTHORS
/usr/share/doc/xkeyboard-config/COPYING
/usr/share/doc/xkeyboard-config/HOWTO.testing
/usr/share/doc/xkeyboard-config/HOWTO.transition
/usr/share/doc/xkeyboard-config/NEWS
/usr/share/doc/xkeyboard-config/README
/usr/share/doc/xkeyboard-config/README.config
/usr/share/doc/xkeyboard-config/README.enhancing
/usr/share/doc/xkeyboard-config/README.symbols
/usr/share/doc/tzdata/
/usr/share/doc/tzdata/README
/usr/share/doc/tzdata/theory.html
/usr/share/doc/tzdata/tz-art.html
/usr/share/doc/tzdata/tz-link.html
[csr@rhel-lab1 ~]$ du -sh docu*.*
59M     documentation.tar
19M     documentation.tar.gz

using J for compression

[csr@rhel-lab1 ~]$ tar -cjvf documentation.tar.bz2 /usr/share/doc | more
tar: Removing leading `/' from member names
/usr/share/doc/
/usr/share/doc/hwdata/
/usr/share/doc/hwdata/LICENSE
/usr/share/doc/xkeyboard-config/
/usr/share/doc/xkeyboard-config/AUTHORS
/usr/share/doc/xkeyboard-config/COPYING
/usr/share/doc/xkeyboard-config/HOWTO.testing
/usr/share/doc/xkeyboard-config/HOWTO.transition
/usr/share/doc/xkeyboard-config/NEWS
/usr/share/doc/xkeyboard-config/README
/usr/share/doc/xkeyboard-config/README.config
/usr/share/doc/xkeyboard-config/README.enhancing
/usr/share/doc/xkeyboard-config/README.symbols
/usr/share/doc/tzdata/
[csr@rhel-lab1 ~]$ du -sh docu*.*
59M     documentation.tar
16M     documentation.tar.bz2
19M     documentation.tar.gz

Listing the gz file content

[csr@rhel-lab1 ~]$ tar -ttzvf documentation.tar.gz | more
drwxr-xr-x root/root         0 2024-04-09 17:31 usr/share/doc/
drwxr-xr-x root/root         0 2024-04-08 14:55 usr/share/doc/hwdata/
-rw-r--r-- root/root       175 2023-08-21 01:22 usr/share/doc/hwdata/LICENSE
drwxr-xr-x root/root         0 2024-04-08 14:55 usr/share/doc/xkeyboard-config/
-rw-r--r-- root/root       510 2021-06-08 15:20 usr/share/doc/xkeyboard-config/AUTHORS
-rw-r--r-- root/root      9244 2021-06-08 15:20 usr/share/doc/xkeyboard-config/COPYING
-rw-r--r-- root/root       861 2021-06-08 15:20 usr/share/doc/xkeyboard-config/HOWTO.testing
-rw-r--r-- root/root      2303 2021-06-08 15:20 usr/share/doc/xkeyboard-config/HOWTO.transition
-rw-r--r-- root/root      5108 2021-06-08 15:20 usr/share/doc/xkeyboard-config/NEWS
-rw-r--r-- root/root      1627 2021-06-08 15:20 usr/share/doc/xkeyboard-config/READ

untar file and view the content using tree

[csr@rhel-lab1 ~]$ mkdir doctests
[csr@rhel-lab1 ~]$ mv documentation.tar* /doctests/
mv: target '/doctests/' is not a directory
[csr@rhel-lab1 ~]$ mv documentation.tar* ~/doctests/
[csr@rhel-lab1 ~]$ cd doctests/
[csr@rhel-lab1 doctests]$ ls
documentation.tar  documentation.tar.bz2  documentation.tar.gz
[csr@rhel-lab1 doctests]$ tar -xzvf documentation.tar.gz 
[csr@rhel-lab1 doctests]$ ls -la
total 93816
drwxr-xr-x.  3 csr csr       99 Apr 15 18:51 .
drwx------. 17 csr csr     4096 Apr 15 18:49 ..
-rw-r--r--.  1 csr csr 61173760 Apr 15 18:33 documentation.tar
-rw-r--r--.  1 csr csr 15930018 Apr 15 18:44 documentation.tar.bz2
-rw-r--r--.  1 csr csr 18954095 Apr 15 18:42 documentation.tar.gz
drwxr-xr-x.  3 csr csr       19 Apr 15 18:51 usr
[csr@rhel-lab1 doctests]$ tree usr | more
usr
└── share
    └── doc
        ├── abattis-cantarell-fonts
        │   ├── NEWS
        │   └── README.md
        ├── accountsservice
        │   ├── AUTHORS
        │   └── README.md
        ├── adcli
        │   ├── AUTHORS
        │   ├── ChangeLog
        │   ├── COPYING
        │   ├── NEWS
        │   └── README
        ├── adobe-mappings-cmap
        │   ├── README.md
        │   └── VERSIONS.txt
        ├── adobe-mappings-pdf
        │   └── README.md
        ├── adobe-source-code-pro-fonts
        │   └── README.md
        ├── alsa-lib
        │   ├── asoundrc.txt

extract a single file from the tar document

[csr@rhel-lab1 doctests]$ tar -xzvf documentation.tar.gz usr/share/doc/gdisk/gdisk_test.sh
usr/share/doc/gdisk/gdisk_test.sh
[csr@rhel-lab1 doctests]$ 
[csr@rhel-lab1 doctests]$ tree usr
usr
└── share
    └── doc
        └── gdisk
            └── gdisk_test.sh

using gunzip

cloud_user@server1: ~ $ ls
audit  build  init_pass  mariadb_repo_setup  Public  Templates  wget-1.19.5-8.el8_1.1.x86_64.rpm
cloud_user@server1: ~ $ gzip wget-1.19.5-8.el8_1.1.x86_64.rpm 
cloud_user@server1: ~ $ ll
total 740
drwxrwxr-x. 2 cloud_user cloud_user     74 Sep  8  2020 audit
drwxrwxr-x. 2 cloud_user cloud_user     55 Sep  8  2020 build
-rw-r--r--. 1 cloud_user cloud_user      1 Apr 30  2021 init_pass
-rwxrwxr-x. 1 cloud_user cloud_user  19519 Sep  9  2020 mariadb_repo_setup
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Public
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Templates
-rw-r--r--. 1 cloud_user cloud_user 729756 Sep  9  2020 wget-1.19.5-8.el8_1.1.x86_64.rpm.gz

unzip it

cloud_user@server1: ~ $ gunzip wget-1.19.5-8.el8_1.1.x86_64.rpm.gz 
cloud_user@server1: ~ $ ll
total 760
drwxrwxr-x. 2 cloud_user cloud_user     74 Sep  8  2020 audit
drwxrwxr-x. 2 cloud_user cloud_user     55 Sep  8  2020 build
-rw-r--r--. 1 cloud_user cloud_user      1 Apr 30  2021 init_pass
-rwxrwxr-x. 1 cloud_user cloud_user  19519 Sep  9  2020 mariadb_repo_setup
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Public
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Templates
-rw-r--r--. 1 cloud_user cloud_user 752504 Sep  9  2020 wget-1.19.5-8.el8_1.1.x86_64.rpm
cloud_user@server1: ~ $

same apply to bzip

cloud_user@server1: ~ $ bzip2 wget-1.19.5-8.el8_1.1.x86_64.rpm 
cloud_user@server1: ~ $ ll
total 744
drwxrwxr-x. 2 cloud_user cloud_user     74 Sep  8  2020 audit
drwxrwxr-x. 2 cloud_user cloud_user     55 Sep  8  2020 build
-rw-r--r--. 1 cloud_user cloud_user      1 Apr 30  2021 init_pass
-rwxrwxr-x. 1 cloud_user cloud_user  19519 Sep  9  2020 mariadb_repo_setup
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Public
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Templates
-rw-r--r--. 1 cloud_user cloud_user 736128 Sep  9  2020 wget-1.19.5-8.el8_1.1.x86_64.rpm.bz2
cloud_user@server1: ~ $ bunzip2 wget-1.19.5-8.el8_1.1.x86_64.rpm.bz2 
cloud_user@server1: ~ $ ll
total 760
drwxrwxr-x. 2 cloud_user cloud_user     74 Sep  8  2020 audit
drwxrwxr-x. 2 cloud_user cloud_user     55 Sep  8  2020 build
-rw-r--r--. 1 cloud_user cloud_user      1 Apr 30  2021 init_pass
-rwxrwxr-x. 1 cloud_user cloud_user  19519 Sep  9  2020 mariadb_repo_setup
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Public
drwxr-xr-x. 2 cloud_user cloud_user      6 May  8  2019 Templates
-rw-r--r--. 1 cloud_user cloud_user 752504 Sep  9  2020 wget-1.19.5-8.el8_1.1.x86_64.rpm
cloud_user@server1: ~ $

Task 2

Using brackets and how to create multiple files

cloud_user@server1: ~ $ mkdir -p ~/code/ursula/{cloudform,xml} ~/code/mortimer/json
cloud_user@server1: ~ $ tree code
code
├── mortimer
│   └── json
└── ursula
    ├── cloudform
    └── xml

5 directories, 0 files
cloud_user@server1: ~ $ 

cloud_user@server1: ~ $ touch ~/code/ursula/{file1,file2,file3}.json ~/code/ursula/file{1,2,3}.xml
cloud_user@server1: ~ $ tree code
code
├── mortimer
│   └── json
└── ursula
    ├── cloudform
    ├── file1.json
    ├── file1.xml
    ├── file2.json
    ├── file2.xml
    ├── file3.json
    ├── file3.xml
    └── xml

5 directories, 6 files

cloud_user@server1: ~ $ touch ~/code/mortimer/{file1,file2,file3}.cf
cloud_user@server1: ~ $ tree
.
├── audit
│   ├── devsys05-account-audit.log
│   └── devsys08-account-audit.log
├── build
│   ├── devsys12-account-audit.log
│   └── dnf.log
├── code
│   ├── mortimer
│   │   ├── file1.cf
│   │   ├── file2.cf
│   │   ├── file3.cf
│   │   └── json
│   └── ursula
│       ├── cloudform
│       ├── file1.json
│       ├── file1.xml
│       ├── file2.json
│       ├── file2.xml
│       ├── file3.json
│       ├── file3.xml
│       └── xml
├── init_pass
├── mariadb_repo_setup
├── Public
├── Templates
└── wget-1.19.5-8.el8_1.1.x86_64.rpm

moving files around

cloud_user@server1: ~ $ mv ~/code/ursula/*.xml ~/code/ursula/xml/
cloud_user@server1: ~ $ tree
.
├── audit
│   ├── devsys05-account-audit.log
│   └── devsys08-account-audit.log
├── build
│   ├── devsys12-account-audit.log
│   └── dnf.log
├── code
│   ├── mortimer
│   │   ├── file1.cf
│   │   ├── file2.cf
│   │   ├── file3.cf
│   │   └── json
│   └── ursula
│       ├── cloudform
│       ├── file1.json
│       ├── file2.json
│       ├── file3.json
│       └── xml
│           ├── file1.xml
│           ├── file2.xml
│           └── file3.xml
├── init_pass
├── mariadb_repo_setup
├── Public
├── Templates
└── wget-1.19.5-8.el8_1.1.x86_64.rpm

10 directories, 16 files
cloud_user@server1: ~ $ 
cloud_user@server1: ~ $ mv ~/code/ursula/*.json ~/code/mortimer/json/
cloud_user@server1: ~ $ tree code
code
├── mortimer
│   ├── file1.cf
│   ├── file2.cf
│   ├── file3.cf
│   └── json
│       ├── file1.json
│       ├── file2.json
│       └── file3.json
└── ursula
    ├── cloudform
    └── xml
        ├── file1.xml
        ├── file2.xml
        └── file3.xml

5 directories, 9 files
cloud_user@server1: ~ $ 
cloud_user@server1: mortimer $ mv *.cf ../ursula/cloudform/
cloud_user@server1: mortimer $ cd
cloud_user@server1: ~ $ tree code
code
├── mortimer
│   └── json
│       ├── file1.json
│       ├── file2.json
│       └── file3.json
└── ursula
    ├── cloudform
    │   ├── file1.cf
    │   ├── file2.cf
    │   └── file3.cf
    └── xml
        ├── file1.xml
        ├── file2.xml
        └── file3.xml

5 directories, 9 files
cloud_user@server1: ~ $ 
cloud_user@server1: ~ $ cp ~/code/ursula/cloudform/ ~/code/mortimer/ -r
cloud_user@server1: ~ $ tree code
code
├── mortimer
│   ├── cloudform
│   │   ├── file1.cf
│   │   ├── file2.cf
│   │   └── file3.cf
│   └── json
│       ├── file1.json
│       ├── file2.json
│       └── file3.json
└── ursula
    ├── cloudform
    │   ├── file1.cf
    │   ├── file2.cf
    │   └── file3.cf
    └── xml
        ├── file1.xml
        ├── file2.xml
        └── file3.xml

6 directories, 12 files
cloud_user@server1: ~ $ rm -rf ~/code/ursula/cloudform/
cloud_user@server1: ~ $ tree code
code
├── mortimer
│   ├── cloudform
│   │   ├── file1.cf
│   │   ├── file2.cf
│   │   └── file3.cf
│   └── json
│       ├── file1.json
│       ├── file2.json
│       └── file3.json
└── ursula
    └── xml
        ├── file1.xml
        ├── file2.xml
        └── file3.xml

5 directories, 9 files
cloud_user@server1: ~ $

task 3 creating softlinks and hardlinks

cloud_user@server1: links $ ll
total 0
cloud_user@server1: links $ touch original 
cloud_user@server1: links $ ll -i #Use -i to show the inode nuber
total 0
12583416 -rw-rw-r--. 1 cloud_user cloud_user 0 Apr 16 01:20 original
cloud_user@server1: links $

creating a softlink

cloud_user@server1: links $ ln -s original softlink
cloud_user@server1: links $ ll -i
total 0
12583416 -rw-rw-r--. 1 cloud_user cloud_user 0 Apr 16 01:20 original
12583419 lrwxrwxrwx. 1 cloud_user cloud_user 8 Apr 16 01:22 softlink -> original

creating a softlink to a folder, we can notice they have different inode numbers

cloud_user@server1: links $ mkdir directory
cloud_user@server1: links $ ln -s directory/ otherdirectory
cloud_user@server1: links $ ls -li
total 0
33560168 drwxrwxr-x. 2 cloud_user cloud_user  6 Apr 16 01:22 directory
12583416 -rw-rw-r--. 1 cloud_user cloud_user  0 Apr 16 01:20 original
12583420 lrwxrwxrwx. 1 cloud_user cloud_user 10 Apr 16 01:22 otherdirectory -> directory/
12583419 lrwxrwxrwx. 1 cloud_user cloud_user  8 Apr 16 01:22 softlink -> original

creating a hardlink we can notice the inode is the same

cloud_user@server1: links $ ln original hardlink
cloud_user@server1: links $ ls -li
total 0
33560168 drwxrwxr-x. 2 cloud_user cloud_user  6 Apr 16 01:22 directory
12583416 -rw-rw-r--. 2 cloud_user cloud_user  0 Apr 16 01:20 hardlink
12583416 -rw-rw-r--. 2 cloud_user cloud_user  0 Apr 16 01:20 original
12583420 lrwxrwxrwx. 1 cloud_user cloud_user 10 Apr 16 01:22 otherdirectory -> directory/
12583419 lrwxrwxrwx. 1 cloud_user cloud_user  8 Apr 16 01:22 softlink -> original

creating a softlink to fstab

cloud_user@server1: links $ ln -s /etc/fstab softtab
cloud_user@server1: links $ ll -i
total 0
33560168 drwxrwxr-x. 2 cloud_user cloud_user  6 Apr 16 01:22 directory
12583416 -rw-rw-r--. 2 cloud_user cloud_user  0 Apr 16 01:20 hardlink
12583416 -rw-rw-r--. 2 cloud_user cloud_user  0 Apr 16 01:20 original
12583420 lrwxrwxrwx. 1 cloud_user cloud_user 10 Apr 16 01:22 otherdirectory -> directory/
12583419 lrwxrwxrwx. 1 cloud_user cloud_user  8 Apr 16 01:22 softlink -> original
12583421 lrwxrwxrwx. 1 cloud_user cloud_user 10 Apr 16 01:25 softtab -> /etc/fstab

now a hardlink to fstab

cloud_user@server1: links $ ln /etc/fstab hardtab
ln: failed to create hard link 'hardtab' => '/etc/fstab': Operation not permitted
cloud_user@server1: links $ sudo ln /etc/fstab hardtab
[sudo] password for cloud_user: 
cloud_user@server1: links $ ll -i
total 4
33560168 drwxrwxr-x. 2 cloud_user cloud_user   6 Apr 16 01:22 directory
12583416 -rw-rw-r--. 2 cloud_user cloud_user   0 Apr 16 01:20 hardlink
   71951 -rw-r--r--. 2 root       root       475 May  8  2019 hardtab
12583416 -rw-rw-r--. 2 cloud_user cloud_user   0 Apr 16 01:20 original
12583420 lrwxrwxrwx. 1 cloud_user cloud_user  10 Apr 16 01:22 otherdirectory -> directory/
12583419 lrwxrwxrwx. 1 cloud_user cloud_user   8 Apr 16 01:22 softlink -> original
12583421 lrwxrwxrwx. 1 cloud_user cloud_user  10 Apr 16 01:25 softtab -> /etc/fstab

finding where a hardlink belongs using the inode to search

cloud_user@server1: links $ find / -inum 71951 2> /dev/null
/proc/2428/oom_adj
/etc/fstab
/home/cloud_user/links/hardtab

Now we are going to find by inode number and also execute an ls -li

cloud_user@server1: links $ find / -inum 71951 -exec ls -li {} \; 2> /dev/null
71951 -rw-r--r--. 1 root root 0 Apr 16 01:27 /proc/2428/oom_adj
71951 -rw-r--r--. 2 root root 475 May  8  2019 /etc/fstab
71951 -rw-r--r--. 2 root root 475 May  8  2019 /home/cloud_user/links/hardtab
cloud_user@server1: links $

cloud_user@server1: links $ find ./ -inum 12583416
./original
./hardlink
cloud_user@server1: links $

Task 4

creating a working folder

loud_user@server1: ~ $ sudo -i
[sudo] password for cloud_user: 
root@server1: ~ # mkdir /project-phoenix
root@server1: ~ # ls
anaconda-ks.cfg  aws-cfn-bootstrap-1.4  original-ks.cfg
root@server1: ~ # pwd
/root
root@server1: ~ # cd ..
root@server1: / # ls
bin  boot  data  dev  etc  home  lib  lib64  media  mnt  opt  proc  project-phoenix  root  run  sbin  srv  swapfile  sys  tmp  usr  var
root@server1: / # cd /home/
root@server1: home # ls -ld /project-phoenix/
drwxr-xr-x. 2 root root 6 Apr 16 02:11 /project-phoenix/

creating users

root@server1: home # 
root@server1: home # useradd -m -g users -G devops snuffy ; passwd snuffy
Changing password for user snuffy.
New password: 
Retype new password: 
passwd: all authentication tokens updated successfully.
root@server1: home # useradd -m -g devops -G users ursula ; passwd ursula
Changing password for user ursula.
New password: 
Retype new password: 
Sorry, passwords do not match.
passwd: Authentication token manipulation error
root@server1: home # passwd ursula
Changing password for user ursula.
New password: 
Retype new password: 
Sorry, passwords do not match.
^[[Apasswd: Authentication token manipulation error
root@server1: home # passwd ursula
Changing password for user ursula.
New password: 
Retype new password: 
passwd: all authentication tokens updated successfully.
root@server1: home # useradd -m -g sysadmins -G users mortimer ; passwd mortimer
Changing password for user mortimer.
New password: 
Retype new password: 
passwd: all authentication tokens updated successfully.
root@server1: home # cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
systemd-coredump:x:999:997:systemd Core Dumper:/:/sbin/nologin
systemd-resolve:x:193:193:systemd Resolver:/:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
polkitd:x:998:996:User for polkitd:/:/sbin/nologin
unbound:x:997:995:Unbound DNS resolver:/etc/unbound:/sbin/nologin
sssd:x:996:993:User for sssd:/:/sbin/nologin
insights:x:995:992:Red Hat Insights:/var/lib/insights:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
chrony:x:994:991::/var/lib/chrony:/sbin/nologin
cloud_user:x:1001:1001::/home/cloud_user:/bin/bash
ssm-user:x:1002:1002::/home/ssm-user:/bin/bash
qemu:x:107:107:qemu user:/:/sbin/nologin
rtkit:x:172:172:RealtimeKit:/proc:/sbin/nologin
pulse:x:171:171:PulseAudio System Daemon:/var/run/pulse:/sbin/nologin
usbmuxd:x:113:113:usbmuxd user:/:/sbin/nologin
gluster:x:993:986:GlusterFS daemons:/run/gluster:/sbin/nologin
saslauth:x:992:76:Saslauthd user:/run/saslauthd:/sbin/nologin
geoclue:x:991:985:User for geoclue:/var/lib/geoclue:/sbin/nologin
rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
dnsmasq:x:984:984:Dnsmasq DHCP and DNS server:/var/lib/dnsmasq:/sbin/nologin
pipewire:x:983:982:PipeWire System Daemon:/var/run/pipewire:/sbin/nologin
colord:x:982:981:User for colord:/var/lib/colord:/sbin/nologin
gdm:x:42:42::/var/lib/gdm:/sbin/nologin
radvd:x:75:75:radvd user:/:/sbin/nologin
gnome-initial-setup:x:981:980::/run/gnome-initial-setup/:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
setroubleshoot:x:980:979::/var/lib/setroubleshoot:/sbin/nologin
flatpak:x:979:978:User for flatpak system helper:/:/sbin/nologin
devops:x:1003:1003:DevOps Admin Service Account:/home/devops:/bin/bash
mysql:x:977:976:MySQL server:/var/lib/mysql:/sbin/nologin
snuffy:x:1004:100::/home/snuffy:/bin/bash
ursula:x:1005:1003::/home/ursula:/bin/bash
mortimer:x:1006:49999::/home/mortimer:/bin/bash

Set folder permissions

set the grouup to users and change permissions to folder

root@server1: home # 
root@server1: home # ls -ld /project-phoenix/
drwxr-xr-x. 2 root root 6 Apr 16 02:11 /project-phoenix/
root@server1: home # chown .users /project-phoenix/
root@server1: home # ls -ld /project-phoenix/
drwxr-xr-x. 2 root users 6 Apr 16 02:11 /project-phoenix/
root@server1: home # chmod g+w /project-phoenix/
root@server1: home # ls -ld /project-phoenix/
drwxrwxr-x. 2 root users 6 Apr 16 02:11 /project-phoenix/
root@server1: home #

test permissions

root@server1: home # su snuffy 
snuffy@server1: home $ touch /project-phoenix/snuffy.file1
snuffy@server1: home $ exit
exit
root@server1: home # sudo - ursula
sudo: -: command not found
root@server1: home # su - ursula
[ursula@server1 ~]$ touch /project-phoenix/ursula.file1
[ursula@server1 ~]$ exit
logout
root@server1: home # su - mortimer
[mortimer@server1 ~]$ touch /project-phoenix/mortimer.file1
[mortimer@server1 ~]$ logout
root@server1: home # ls -l /project-phoenix/
total 0
-rw-r--r--. 1 mortimer sysadmins 0 Apr 16 02:18 mortimer.file1
-rw-r--r--. 1 snuffy   users     0 Apr 16 02:18 snuffy.file1
-rw-r--r--. 1 ursula   devops    0 Apr 16 02:18 ursula.file1
root@server1: home #

Change so all users has the same ownership

root@server1: home # ls -ld /project-phoenix/ ; ls -l /project-phoenix/
drwxrwxr-x. 2 root users 68 Apr 16 02:18 /project-phoenix/
total 0
-rw-r--r--. 1 mortimer sysadmins 0 Apr 16 02:18 mortimer.file1
-rw-r--r--. 1 snuffy   users     0 Apr 16 02:18 snuffy.file1
-rw-r--r--. 1 ursula   devops    0 Apr 16 02:18 ursula.file1
root@server1: home # chmod g+s /project-phoenix/
root@server1: home # ls -ld /project-phoenix/
drwxrwsr-x. 2 root users 68 Apr 16 02:18 /project-phoenix/
root@server1: home # su - snuffy
Last login: Tue Apr 16 02:17:55 UTC 2024 on pts/0
[snuffy@server1 ~]$ touch /project-phoenix/snuffy.file2
[snuffy@server1 ~]$ exxit
bash: exxit: command not found...
e^C
[snuffy@server1 ~]$ exit
logout
root@server1: home # su - ursula
Last login: Tue Apr 16 02:18:22 UTC 2024 on pts/0
[ursula@server1 ~]$ touch /project-phoenix/ursula.file2
[ursula@server1 ~]$ exit
logout
root@server1: home # su - mortimer 
Last login: Tue Apr 16 02:18:36 UTC 2024 on pts/0
[mortimer@server1 ~]$ touch /project-phoenix/mortimer.file2
[mortimer@server1 ~]$ exit
logout
root@server1: home # ls -ld /project-phoenix/
drwxrwsr-x. 2 root users 130 Apr 16 02:20 /project-phoenix/
root@server1: home # ls -l /project-phoenix/
total 0
-rw-r--r--. 1 mortimer sysadmins 0 Apr 16 02:18 mortimer.file1
-rw-r--r--. 1 mortimer users     0 Apr 16 02:20 mortimer.file2
-rw-r--r--. 1 snuffy   users     0 Apr 16 02:18 snuffy.file1
-rw-r--r--. 1 snuffy   users     0 Apr 16 02:20 snuffy.file2
-rw-r--r--. 1 ursula   devops    0 Apr 16 02:18 ursula.file1
-rw-r--r--. 1 ursula   users     0 Apr 16 02:20 ursula.file2

make another change to make sure users cannot delete files from other users

root@server1: home # chmod +t /project-phoenix/
root@server1: home # ls -ld /project-phoenix/
drwxrwsr-t. 2 root users 130 Apr 16 02:20 /project-phoenix/ # Notice there is a t at the end of the permissions
root@server1: home # 
root@server1: home # chown .users /project-phoenix/*.*  # change all file groups to users
root@server1: home # ls -l /project-phoenix/
total 0
-rw-r--r--. 1 mortimer users 0 Apr 16 02:18 mortimer.file1
-rw-r--r--. 1 mortimer users 0 Apr 16 02:20 mortimer.file2
-rw-r--r--. 1 snuffy   users 0 Apr 16 02:18 snuffy.file1
-rw-r--r--. 1 snuffy   users 0 Apr 16 02:20 snuffy.file2
-rw-r--r--. 1 ursula   users 0 Apr 16 02:18 ursula.file1
-rw-r--r--. 1 ursula   users 0 Apr 16 02:20 ursula.file2

RHCSA EX200 - Understand and use essential tools

RHCSA EX200 - Input/Output Redirection LAB

Use Input/Output Redirection

Create a Server Health Log File

Create a server health log file that contains a sequential number of outputs with the hostname, date and time, and a simple header:

cloud_user@server1: ~ $ { echo " " ; echo "==== `date` on `hostname` ====" ; df -hT ; }
 
==== Wed May  1 20:53:07 UTC 2024 on server1 ====
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
tmpfs          tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M  1.9G   1% /run
tmpfs          tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G  6.7G  67% /
tmpfs          tmpfs     373M  4.0K  373M   1% /run/user/1001

Rerun the previous command, and output this to a text file:

{ echo " " ; echo "==== `date` on `hostname` ====" ; df -hT ; } > `hostname`-health.txt

Review the output:

cloud_user@server1: ~ $ cat server1-health.txt 
 
==== Wed May  1 20:53:51 UTC 2024 on server1 ====
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
tmpfs          tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M  1.9G   1% /run
tmpfs          tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G  6.7G  67% /
tmpfs          tmpfs     373M  4.0K  373M   1% /run/user/1001

Observe what was added to the file.

Rerun the first echo command to create the server health log file twice more:

{ echo " " ; echo "==== `date` on `hostname` ====" ; df -hT ; } > `hostname`-health.txt

Review the output using cat server1-health.txt again to see how many times the command was run.
Change the server health log file to contain a double redirect to ensure that the initial and subsequent outputs are not overwritten:
```
{ echo " " ; echo "==== `date` on `hostname` ====" ; df -hT ; } >> `hostname`-health.txt
```
Run the above command 2 more times.
Inspect the output again using cat server1-health.txt.

cat server1-health.txt

cloud_user@server1: ~ $ cat server1-health.txt

==== Wed May 1 20:58:43 UTC 2024 on server1 ====
Filesystem     Type      Size Used Avail Use% Mounted on
devtmpfs       devtmpfs 1.8G     0 1.8G   0% /dev
tmpfs          tmpfs     1.9G     0 1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M 1.9G   1% /run
tmpfs          tmpfs     1.9G     0 1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G 6.7G 67% /
tmpfs          tmpfs     373M 4.0K 373M   1% /run/user/1001

==== Wed May 1 21:00:24 UTC 2024 on server1 ====
Filesystem     Type      Size Used Avail Use% Mounted on
devtmpfs       devtmpfs 1.8G     0 1.8G   0% /dev
tmpfs          tmpfs     1.9G     0 1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M 1.9G   1% /run
tmpfs          tmpfs     1.9G     0 1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G 6.7G 67% /
tmpfs          tmpfs     373M 4.0K 373M   1% /run/user/1001

==== Wed May 1 21:00:25 UTC 2024 on server1 ====
Filesystem     Type      Size Used Avail Use% Mounted on
devtmpfs       devtmpfs 1.8G     0 1.8G   0% /dev
tmpfs          tmpfs     1.9G     0 1.9G   0% /dev/shm
tmpfs          tmpfs     1.9G   17M 1.9G   1% /run
tmpfs          tmpfs     1.9G     0 1.9G   0% /sys/fs/cgroup
/dev/xvda2     xfs        20G   14G 6.7G 67% /
tmpfs          tmpfs     373M 4.0K 373M   1% /run/user/1001

Search for Files in the `/home` Directory

Find all the files in the /home directory owned by the cloud_user:
```
find /home -user cloud_user
```
Observe a long list of filenames, along with 2 Permission denied errors at the end.
Generate clean lines of output without the 2 errors:
```
find /home -user cloud_user 2> /dev/null
```

Find out how many clean lines of output there are:

find /home -user cloud_user 2> /dev/null | wc -l

Save the output to a text file:

find /home -user cloud_user 2> /dev/null > cloud_user-files.txt

Ensure the filenames are in the text file:
```
cat cloud_user-files.txt
```
Number the list of filenames, and save them in another text file:
```
nl cloud_user-files.txt > numberedfiles.txt
```
Ensure the numbered filenames are in the text file:
```
cat numberedfiles.txt
```
Sort the numbered lines:
```
sort numberedfiles.txt
```
Observe that because there were no leading zeroes in front of the lower numbers, it doesn't sort properly.
To fix this, run a numeric sort:
```
sort -n numberedfiles.txt
```
Generate a list showing the first-level directories inside /etc:
```
find /etc -maxdepth 1
```
Observe the output includes files that go 1 level further than then /etc directory.
Add on to the previous command to generate a list showing the space used for the first-level directories inside /etc:
```
find /etc -maxdepth 1 -iname "*.*" -exec du -sh {} \;
```
Observe the previous list now includes total space usage for each item.
Rerun the following command, and sort it by space usage from least to most used:
```
find /etc -maxdepth 1 -iname "*.*" -exec du -sh {} \; | sort -h
```
Rerun the previous command, and this time, output it to etc-space-usage.txt:
```
find /etc -maxdepth 1 -iname "*.*" -exec du -sh {} \; | sort -h > etc-space-usage.txt
```
You shouldn't see any output aside from 2 directory errors.
Review the file:
```
less etc-space-usage.txt
```
Observe the files listed and sorted by space usage.

Use `grep` and Regular Expressions to Analyze Text

Find all the files owned by the cloud_user in the /home directory:
```
find /home -user cloud_user
```

Find all the files owned by the cloud_user in the /home directory that contain the word "file":

cloud_user@server1: ~ $ find /home -user cloud_user | grep -i file
/home/cloud_user/.bash_profile
find: ‘/home/ssm-user’/home/cloud_user/numberedfiles.txt
/home/cloud_user/cloud_user-files.txt
: Permission denied
find: ‘/home/devops’: Permission denied

Notice in the output that it only searches for the word "file" in the actual filenames rather than within the contents of the file.

Use the -exec feature of find to find the word "file" in the files themselves:
```
find /home -user cloud_user -exec grep -i file {} \;
```
Find out how many lines of output were found:
```
find /home -user cloud_user -exec grep -i file {} \; | wc -l
```
You should see 140 lines at the bottom of the output.
Count how many lines were generated without errors:
```
find /home -user cloud_user -exec grep -i file {} \; 2> /dev/null | wc -l
```
You should again see 140 lines. Note that this counts only the standard out rather than the standard error.
Utilize the grep command directly to find the word "file" inside all files owned by cloud_user in the /home directory:
```
grep -ir file /usr/share/doc/zip
```
Add a total count of the output to the bottom of the list:
```
grep -ir file /usr/share/doc/zip ; !! | wc -l
```
You should see 965 at the bottom.
Run a case-sensitive search for only the word "file" as lowercase:
```
grep -ir file /usr/share/doc/zip ; grep -r file /usr/share/doc/zip | wc -l
```
You should see 925 at the bottom.

Create a text file containing all the search results for the word "file":

grep -ir file /usr/share/doc/zip ; grep -r file /usr/share/doc/zip > grepoutput.txt

Check the text file output:
```
cat grepoutput.txt
```

RHCSA EX200

Objectives

EX200 Objectives

Study points for the exam

RHCSA EX200 - Understand and use essential tools

RHCSA EX200 - Accessing linux systems LAB

Task 2 - access remote systems using ssh

Task 3 - creating a keygen to ssh to remote server

RHCSA EX200 - VIM Survival kit LAB

1. - Creating opening and exiting a file.

2- Making simple changes to a file

3.- Changing a system file

4.- Simple Navigation

5. - Inserting copying and deleting

RHCSA EX200 - Managing Files LAB

RHCSA EX200 - Input/Output Redirection LAB

Use Input/Output Redirection

Create a Server Health Log File

Search for Files in the /home Directory

Use grep and Regular Expressions to Analyze Text

Search for Files in the `/home` Directory

Use `grep` and Regular Expressions to Analyze Text