General Linux Items / Commands

##How to remount the file system read write (rw) In maintenance mode##

mount -o remount, rw /

##How to unencrypt PDF documents##

http://www.cyberciti.biz/faq/removing-password-from-pdf-on-linux/

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=/home/erik/Destination.pdf -c .setpdfwrite -f /home/erik/source.pdf

##How to reindex spacewalk postgres database##

I was getting all kinds of weird spacewalk errors that all seemed to point to the database.

$sudo  su postgres

$reindexdb --all

At the end I got the following eror:

NOTICE:  table "rhnpackagedeltaelement" was reindexed
reindexdb: reindexing of database "rhnschema" failed: ERROR:  could not create unique index "rhnchecksum_chsum_uq"
DETAIL:  Table contains duplicated values.

I ended up restoring a backed up VM

##To Find directories and sizes##

du -sch .[!.]* * |sort -h

##Removing Old Kernels##

$ sudo yum install yum-utils

$ sudo package-cleanup --oldkernels --count=2

Edit /etc/yum.conf and set installonly_limit:

installonly_limit=2

##Piping a command through mail##

| mail -s "Clam Scan %D" erik@hq38.hohenfels.com

##Get a list of rpm’s off a web page for a script##

http://linux.dell.com/repo/hardware/Linux_Repository_14.12.00/platform_independent/rh60_64/srvadmin-x86_64/ | egrep -o "http:.*rpm" |cut -d "/" -f10

##To delete a server from using Spacewalk

##Delete the server from the WebGUI

##On the Client:

sudo vi /etc/yum/pluginconf.d/rhnplugin.conf

##And change:

[main]
enabled = 1

#to

[main]
enabled = 0

##Then

sudo rm -rf /etc/sysconfig/rhn/systemid

##Remove the spacewalk repos if they are there:

sudo rm /etc/yum.repos.d/spacewalk-client*

##SELinux Love

##First install the trouble shooter

sudo yum install setroubleshoot-server setroubleshoot setools

##Then Search the logs:

sudo cat /var/log/messages | grep sealert (CentOS 6)

or

sudo sealert -a /var/log/audit/audit.log (CentOS 7)

You are going to see something like this:

docker setroubleshoot: SELinux is preventing /usr/bin/bash from ioctl access on the file /usr/bin/distro. For complete SELinux messages. run sealert -l f4eed2fe-d681-412f-ab31-55f704a7cf46

##Do what it says, Bolded above

sudo sealert -l f4eed2fe-d681-412f-ab31-55f704a7cf46

##At the top of the output you will see:

If you believe that bash should be allowed ioctl access on the distro file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# grep distro /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

##Again, do what it says

sudo grep distro /var/log/audit/audit.log | audit2allow -M mypol

##Then

sudo semodule -i mypol.pp

## Grub Edit ##

Make the modifications you want:

$ sudo vi /etc/default/grub

After you edit the above file you need to run:

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

##Installing RootKit Hunter

http://lintut.com/install-rkhunter-in-centos/

Here is the conf file location.

sudo vi /etc/rkhunter.conf

Add:

##RootKit Check
/usr/bin/rkhunter --update
/usr/bin/rkhunter --checkall

##Firewall Commands

##Add Port:

sudo firewall-cmd --zone=public --add-port=161/udp --permanent

##Add Know Service

sudo firewall-cmd --permanent --zone public --add-service samba

##Restart

sudo systemctl restart firewalld.service

##Install Logwatch

##Install the package

sudo yum install logwatch

##Edit the conf file:

sudo vi /usr/share/logwatch/default.conf/logwatch.conf

##Change to High

Detail = High

##Set to send an email

Output = mail

##ClamAV

1 – Install EPEL 7

After you’ve successfully installed your operating system and applied all the updates. You can install the EPEL 7 repository by running this command:

sudo yum install epel-release

2 – Install and configure the ClamAV packages

sudo yum install clamav clamav-scanner-systemd

Yes, it’s enough. When installing these packages all needed packages will be installed by dependency.

Correct a “bad” file path probably written during the compilation by creating a link to the correct file:

sudo ln -s /etc/clamd.d/scan.conf /etc/clamd.conf

Edit the configuration installed by the clamd-scanner package:

sudo vi /etc/clamd.d/scan.conf

Comment the example line:

#Example

Uncomment the LocalSocket config line to enable it:

LocalSocket /var/run/clamd.scan/clamd.sock

Save and quit the text editor.

3 – Turn on the SELinux boolean for antivirus

sudo setsebool -P antivirus_can_scan_system 1

4 – Start the service and enable it at boot

sudo systemctl start clamd@scan
sudo systemctl enable clamd@scan

5 – Install and configure the ClamAV updater

To automatically get the latest virus updates, you need to install the binary used for this task:

sudo yum install clamav-update

Edit the configuration file:

sudo vi /etc/freshclam.conf