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  /Title (linux-troubleshooting.pdf)
  /Creator (Cheatography)
  /Author (Zappmax)
  /Subject (Linux Troubleshooting Cheat Sheet)
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        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
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    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Linux Troubleshooting Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{Zappmax} via \textcolor{DarkBackground}{\uline{cheatography.com/177608/cs/37062/}}}
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  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}Zappmax \\
  \uline{cheatography.com/zappmax} \\
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  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Not Yet Published.\\
   Updated 26th May, 2023.\\
   Page {\thepage} of \pageref{LastPage}.
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  Measure your website readability!\\
  www.readability-score.com
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\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Access Troubleshooting}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Server not reachable}} \newline % Row Count 1 (+ 1)
`\#ping servername` \newline % Row Count 2 (+ 1)
if no sucess search for IP for "servername" with  \newline % Row Count 3 (+ 1)
`\#nslookup servername` \newline % Row Count 4 (+ 1)
`\#ping IP-Servername` \newline % Row Count 5 (+ 1)
If IP-servername is pingable check:  \newline % Row Count 6 (+ 1)
`/etc/host` \newline % Row Count 7 (+ 1)
`/etc/resolv.conf` \newline % Row Count 8 (+ 1)
`/etc/nsswitch.conf` \newline % Row Count 9 (+ 1)
If IP-servername is not pingable \newline % Row Count 10 (+ 1)
ping another server with name and ip \newline % Row Count 11 (+ 1)
Check if your machine has ip-adress `\#ip -c -b a \newline % Row Count 12 (+ 1)
 get gateway-ip with `\#netstat -rnv` and check destination 0.0.0.0 to gateway-ip \newline % Row Count 14 (+ 2)
ping gateway -ip  \newline % Row Count 15 (+ 1)
check local physics cable etc. \newline % Row Count 16 (+ 1)
\{\{nl\}\} \newline % Row Count 17 (+ 1)
{\bf{App or website not reachable}} \newline % Row Count 18 (+ 1)
ping servername and server-ip \newline % Row Count 19 (+ 1)
if success connect to service `\#telnet ip port` \newline % Row Count 20 (+ 1)
if not success login into server check services eg. `\#ps -ef |grep -i network` \newline % Row Count 22 (+ 2)
or `\#systemctl status \textless{}service\textgreater{}` or `'systemctl -{}-failed` \newline % Row Count 24 (+ 2)
{\bf{Cannot ssh  as root/user}} \newline % Row Count 25 (+ 1)
check if root is not permittet `\#/etc/ssh/sshd\_conf` \newline % Row Count 27 (+ 2)
check `\#less /var/log/secure` \newline % Row Count 28 (+ 1)
no user or nologin shell  \newline % Row Count 29 (+ 1)
check `\#id \textless{}user\textgreater{}` \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Access Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{check `\#less /etc/passwd` \newline % Row Count 1 (+ 1)
{\bf{Firewall}} \newline % Row Count 2 (+ 1)
check `\#service iptables status` \newline % Row Count 3 (+ 1)
or check `\#systemctl status iptables.service` \newline % Row Count 4 (+ 1)
or check `\#ps -ef|grep iptable` \newline % Row Count 5 (+ 1)
or check `\#systemctl status firewalld` \newline % Row Count 6 (+ 1)
try to temp disable firewall `\#systemctl disable firewalld` \newline % Row Count 8 (+ 2)
{\bf{Terminal or Client is not working}} \newline % Row Count 9 (+ 1)
check correct port user and password syntax% Row Count 10 (+ 1)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Filesystem Troubleshooting}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{If you cannot CD into Dir or cannot open file or run a script}} \newline % Row Count 2 (+ 2)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 3 (+ 1)
Dir/file  not existing \newline % Row Count 4 (+ 1)
check path relative  or absolute \newline % Row Count 5 (+ 1)
check permissions \newline % Row Count 6 (+ 1)
check file type \newline % Row Count 7 (+ 1)
check parent dir permissons \newline % Row Count 8 (+ 1)
check for hidden dir \newline % Row Count 9 (+ 1)
\{\{nl\}\} \newline % Row Count 10 (+ 1)
{\bf{Trouble to find files or dir}} \newline % Row Count 11 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 12 (+ 1)
command find or locate \newline % Row Count 13 (+ 1)
correct syntax: `\#find /path  - type {[}d,f{]} -name 'my\_dir' or 'my\_file'` \newline % Row Count 15 (+ 2)
file/dir exits? \newline % Row Count 16 (+ 1)
\{\{nl\}\} \newline % Row Count 17 (+ 1)
{\bf{Cannot create links}} \newline % Row Count 18 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-- \newline % Row Count 19 (+ 1)
which type of link hard or symbolic \newline % Row Count 20 (+ 1)
syntax source first then target \newline % Row Count 21 (+ 1)
check permissions \newline % Row Count 22 (+ 1)
source or target file/dir missing or not existing \newline % Row Count 23 (+ 1)
\{\{nl\}\} \newline % Row Count 24 (+ 1)
{\bf{Cannot write to a file}} \newline % Row Count 25 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 26 (+ 1)
check if it exists \newline % Row Count 27 (+ 1)
check abs or rel path \newline % Row Count 28 (+ 1)
file type \newline % Row Count 29 (+ 1)
check parent dir permissions \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Filesystem Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{check for hidden file \newline % Row Count 1 (+ 1)
check for file is open by an another user \newline % Row Count 2 (+ 1)
run `\#getfacl` \newline % Row Count 3 (+ 1)
\{\{nl\}\} \newline % Row Count 4 (+ 1)
{\bf{Cannot Move/Rename/Delete/Copy file}} \newline % Row Count 5 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 7 (+ 2)
check if it exists \newline % Row Count 8 (+ 1)
check abs or rel path \newline % Row Count 9 (+ 1)
file type \newline % Row Count 10 (+ 1)
check parent dir permissions \newline % Row Count 11 (+ 1)
check for hidden file \newline % Row Count 12 (+ 1)
command syntax  `\#mv; cp;   "Source then Target"` \newline % Row Count 13 (+ 1)
\{\{nl\}\} \newline % Row Count 14 (+ 1)
{\bf{Cannot change file permissions/ownership}} \newline % Row Count 15 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 16 (+ 1)
check if file exists \newline % Row Count 17 (+ 1)
check abs. or rel path \newline % Row Count 18 (+ 1)
check  file ownership (user and group) \newline % Row Count 19 (+ 1)
check Permissions \newline % Row Count 20 (+ 1)
check parent dir permissions \newline % Row Count 21 (+ 1)
check for hidden file \newline % Row Count 22 (+ 1)
command syntax: `\#chown  or chmod (user then file)` \newline % Row Count 24 (+ 2)
command with recursive option -R \newline % Row Count 25 (+ 1)
only root can change the file ownership \newline % Row Count 26 (+ 1)
\{\{nl\}\} \newline % Row Count 27 (+ 1)
{\bf{Cannot view others users files}} \newline % Row Count 28 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 29 (+ 1)
check if file exists \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Filesystem Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{check abs. or rel path \newline % Row Count 1 (+ 1)
check  file ownership (user and group) \newline % Row Count 2 (+ 1)
check Permissions \newline % Row Count 3 (+ 1)
check parent dir permissions \newline % Row Count 4 (+ 1)
check for hidden file \newline % Row Count 5 (+ 1)
command syntax \newline % Row Count 6 (+ 1)
only root can view any files \newline % Row Count 7 (+ 1)
\{\{nl\}\} \newline % Row Count 8 (+ 1)
{\bf{Cannot change password}} \newline % Row Count 9 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 10 (+ 1)
check if file exists \newline % Row Count 11 (+ 1)
check abs. or rel path \newline % Row Count 12 (+ 1)
check  file ownership (user and group) \newline % Row Count 13 (+ 1)
check Permissions \newline % Row Count 14 (+ 1)
check parent dir permissions \newline % Row Count 15 (+ 1)
check for hidden file \newline % Row Count 16 (+ 1)
check command syntax: \#passw \textless{}user\textgreater{}` \newline % Row Count 17 (+ 1)
only root can change pw of any user \newline % Row Count 18 (+ 1)
\{\{nl\}\} \newline % Row Count 19 (+ 1)
{\bf{Disk space full}} \newline % Row Count 20 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 21 (+ 1)
ckeck : `\#df -h` \newline % Row Count 22 (+ 1)
check HD status:  `\#badblocks -v /dev/DISK` or `/dev/sda` \newline % Row Count 24 (+ 2)
check `\#iostat` \newline % Row Count 25 (+ 1)
\{\{nl\}\} \newline % Row Count 26 (+ 1)
{\bf{Delete old files}} \newline % Row Count 27 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 28 (+ 1)
command: `\#rm` \newline % Row Count 29 (+ 1)
syntax:  \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Filesystem Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{`find /path/to/files -type f -name '*.examples' -mtime +30 -exec rm \{\} \textbackslash{};` \newline % Row Count 2 (+ 2)
\{\{nl\}\} \newline % Row Count 3 (+ 1)
{\bf{Filesystem is corrupted}} \newline % Row Count 4 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 5 (+ 1)
filesystem partitions: `/var`; `/etc`; `/root`; `/home` \newline % Row Count 7 (+ 2)
check file system : `\#df` , `\#fdisk -l` \newline % Row Count 8 (+ 1)
check logs in `/var/log/messages`  or `/var/log/syslog` \newline % Row Count 10 (+ 2)
run `\#fsck` on block device (eg /dev/sda) not on mount point \newline % Row Count 12 (+ 2)
unmount filesystem the run `\#fsck` \newline % Row Count 13 (+ 1)
\{\{nl\}\} \newline % Row Count 14 (+ 1)
{\bf{Corrupted /etc/fstab}} \newline % Row Count 15 (+ 1)
-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}-{}- \newline % Row Count 16 (+ 1)
check filesystem: `\#df` \newline % Row Count 17 (+ 1)
cat or `\#less /etc/fstab` \newline % Row Count 18 (+ 1)
system not booting:  incorrect entry in fstab or fstab deleted \newline % Row Count 20 (+ 2)
Steps to do: \newline % Row Count 21 (+ 1)
*boot in rescue mode mounting a cd or cd-iso image \newline % Row Count 23 (+ 2)
*choose option 1 to mount root fs \newline % Row Count 24 (+ 1)
*fix the  `etc/fstab file` \newline % Row Count 25 (+ 1)
*for deleted file run  `\#blkid` \newline % Row Count 26 (+ 1)
\{\{nl\}\}% Row Count 27 (+ 1)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
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\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Administration Troubleshooting}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Out of memory}} \newline % Row Count 1 (+ 1)
`\#free -m -h` \newline % Row Count 2 (+ 1)
`\#top` \newline % Row Count 3 (+ 1)
`\#vmstat` \newline % Row Count 4 (+ 1)
`\#dmesg |grep -i "Out of memory" ` (/var/log/messages or /var/log/syslog) \newline % Row Count 6 (+ 2)
check `\#/etc/sysctl.conf` \newline % Row Count 7 (+ 1)
{\bf{Add Swap Memory}} \newline % Row Count 8 (+ 1)
`\$df -h` \newline % Row Count 9 (+ 1)
`\#dd if=/dev/zero of=/newswap bs=1M count=1024 ` \newline % Row Count 10 (+ 1)
`\#free -m` \newline % Row Count 11 (+ 1)
`\#chmod 600 newswap` \newline % Row Count 12 (+ 1)
`\#mkswap /newswap` \newline % Row Count 13 (+ 1)
`\#swapon /newswap` \newline % Row Count 14 (+ 1)
change ftsab to: /newswap swap swap defaults 0 0 \newline % Row Count 15 (+ 1)
{\bf{Delete Swap space}} \newline % Row Count 16 (+ 1)
`\#swapoff /newswap` \newline % Row Count 17 (+ 1)
`\#rm /newswap` \newline % Row Count 18 (+ 1)
`\#free -m` \newline % Row Count 19 (+ 1)
change your fstab file  \newline % Row Count 20 (+ 1)
{\bf{System rebooted or process is restarting}} \newline % Row Count 21 (+ 1)
`\#systemctl status \textless{}process\textgreater{}` \newline % Row Count 22 (+ 1)
`\#uptime` \newline % Row Count 23 (+ 1)
`\#top` \newline % Row Count 24 (+ 1)
`\#dmesg` \newline % Row Count 25 (+ 1)
`\#iostat -xz 1` \newline % Row Count 26 (+ 1)
`\#journalctl` \newline % Row Count 27 (+ 1)
Check system logs: /var/log/messages /var/log/syslog /var/log/boot.log \newline % Row Count 29 (+ 2)
Check app logs  \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Administration Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Unable to receive an IP Address}} \newline % Row Count 1 (+ 1)
check DHCP Server \newline % Row Count 2 (+ 1)
check network virtual setting \newline % Row Count 3 (+ 1)
`\#check network hardware setting` \newline % Row Count 4 (+ 1)
lspci | egrep -i 'eth|wifi|wireless' \newline % Row Count 5 (+ 1)
`\#nmcli -p dev` \newline % Row Count 6 (+ 1)
`\#ip  -h -c address` \newline % Row Count 7 (+ 1)
`\#ifup \textless{}interface\textgreater{}   ifconfig up \textless{}interface\textgreater{}` \newline % Row Count 8 (+ 1)
`\#systemctl restart network` \newline % Row Count 9 (+ 1)
check config files  \seqsplit{/etc/sysconfig/network-scripts/ifcfg-enp0s3} or ifcfg-eth0 \newline % Row Count 11 (+ 2)
{\bf{IP assigned but no reachability}} \newline % Row Count 12 (+ 1)
check to which network you are connected to use ifconfig or ip a  \newline % Row Count 14 (+ 2)
ping your gateway \newline % Row Count 15 (+ 1)
`\#netstat -rnv` \newline % Row Count 16 (+ 1)
`\#ethtool or mii-tool` \newline % Row Count 17 (+ 1)
`\#ifup \textless{}interface\textgreater{}` \newline % Row Count 18 (+ 1)
`\#systemctl resart network` \newline % Row Count 19 (+ 1)
`\#ifconfig or ip  -4 \textless{}-6\textgreater{} -c add` \newline % Row Count 20 (+ 1)
try to turn off temporarely the firewall \newline % Row Count 21 (+ 1)
{\bf{What if can't run a specific command}} \newline % Row Count 22 (+ 1)
 check permission and ownership \newline % Row Count 23 (+ 1)
check abs. and rel. path \newline % Row Count 24 (+ 1)
`\#echo \$PATH` \newline % Row Count 25 (+ 1)
check for missing or nit installed sw \newline % Row Count 26 (+ 1)
`\#whereis \textless{}sw\textgreater{}` \newline % Row Count 27 (+ 1)
`\#yum provides \textless{}packet\textgreater{}   or dnf` \newline % Row Count 28 (+ 1)
`\#yum seach telnet` \newline % Row Count 29 (+ 1)
{\bf{Password not changeable}} \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Administration Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{check file /etc/passwd  \newline % Row Count 1 (+ 1)
and /etc/shadow( pwconv will recreate file) \newline % Row Count 2 (+ 1)
user exists correct written ? \newline % Row Count 3 (+ 1)
be root \newline % Row Count 4 (+ 1)
`\#passwd \textless{}user\textgreater{}` \newline % Row Count 5 (+ 1)
after changes in /etc/shadow use pwconv (PW of each \newline % Row Count 7 (+ 2)
user has to set again) \newline % Row Count 8 (+ 1)
{\bf{User has no home dir}} \newline % Row Count 9 (+ 1)
dir not existing \newline % Row Count 10 (+ 1)
dir exists but no entry in /etc/passwd \newline % Row Count 11 (+ 1)
check permission ,ownership and spelling of dir \newline % Row Count 12 (+ 1)
{\bf{Change words in files}} \newline % Row Count 13 (+ 1)
use vi: :1,\$s/oldword/newword/ \newline % Row Count 14 (+ 1)
use sed:  \newline % Row Count 15 (+ 1)
`\#sed -i 's/oldsring/newstring/g' \textless{}filename\textgreater{}` \newline % Row Count 16 (+ 1)
{\bf{sed command}} \newline % Row Count 17 (+ 1)
tbd \newline % Row Count 18 (+ 1)
{\bf{Kill Process, User, Terminal}} \newline % Row Count 19 (+ 1)
Find process ID (PID) `\#ps -ef` \newline % Row Count 20 (+ 1)
`\#kill \textless{}PID\textgreater{}` \newline % Row Count 21 (+ 1)
`\#kill -9 \textless{}pid\textgreater{}` brutal kill \newline % Row Count 22 (+ 1)
`\#pkill \textless{}process name\textgreater{}` \newline % Row Count 23 (+ 1)
`\#killall \textless{}process name\textgreater{}`  \newline % Row Count 24 (+ 1)
`{\bf{ root pw recovery}}` \newline % Row Count 25 (+ 1)
restart computer (physical console  access nessesary) \newline % Row Count 27 (+ 2)
edit grub, search for `ro` change to: \newline % Row Count 28 (+ 1)
`rw init=/sysroot/bin/sh` \newline % Row Count 29 (+ 1)
press \textless{}ctrl x\textgreater{} \newline % Row Count 30 (+ 1)
} \tn 
\end{tabularx}
\par\addvspace{1.3em}

\vfill
\columnbreak
\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Administration Troubleshooting (cont)}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{system reboots in single user mode \newline % Row Count 1 (+ 1)
`\textgreater{}passwd root' \newline % Row Count 2 (+ 1)
`\textgreater{}change pw` \newline % Row Count 3 (+ 1)
`\textgreater{}touch /.autorelable' \newline % Row Count 4 (+ 1)
`\textgreater{}exit` \newline % Row Count 5 (+ 1)
reboot \newline % Row Count 6 (+ 1)
{\bf{ logged in users}} \newline % Row Count 7 (+ 1)
`\#last` \newline % Row Count 8 (+ 1)
{\bf{ System running slow}} \newline % Row Count 9 (+ 1)
Check disk space (df -h and du) \newline % Row Count 10 (+ 1)
Check processing (top, free, lsmem, cat /proc/meminfo,  vmstat,  \newline % Row Count 12 (+ 2)
    pmap \textless{}PID\textgreater{}, dmidecode, lscpu, /proc/cpuinf) \newline % Row Count 13 (+ 1)
Check disk issues (iostat -y 5, lsof) \newline % Row Count 14 (+ 1)
Check networking (tcpdump -i \textless{}interface\textgreater{} , lsof -i -P -n |grep -i listen,  \newline % Row Count 16 (+ 2)
   netstat -plnt or ss -plnt, iftop) \newline % Row Count 17 (+ 1)
Check uptime (uptime) \newline % Row Count 18 (+ 1)
Check logs  \newline % Row Count 19 (+ 1)
check hw status log into system  \newline % Row Count 20 (+ 1)
Other external tools (htop, itop, iptraf, psacct) \newline % Row Count 21 (+ 1)
{\bf{Rollback updates and patches}} \newline % Row Count 22 (+ 1)
Package or patch  \newline % Row Count 23 (+ 1)
`\#dnf history  ` \newline % Row Count 24 (+ 1)
`\#dnf history undo \textless{}id\textgreater{} ` \newline % Row Count 25 (+ 1)
Update (upgrade  does not workold obsolete packages are lost) \newline % Row Count 27 (+ 2)
`\#dnf history undo \textless{}id\textgreater{}`% Row Count 28 (+ 1)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{System Recovery}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Additional Knowledge and Tools}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}