List all ports
# netstat -a | more
List all tcp ports using netstat -at
# netstat -at
List all udp ports using netstat -au
# netstat -au
List only listening ports
# netstat -l
List only listening TCP Ports using netstat -lt
# netstat -lt
List only listening UDP Ports using netstat -lu
# netstat -lu
List only the listening UNIX Ports using netstat -lx
# netstat -lx
Show statistics for all ports
# netstat -s
Show statistics for TCP/UDP ports
# netstat -st
# netstat -su
Display PID and program names
# netstat -pt
Don’t resolve host, port and user name
# netstat -an
Print netstat information continuously
# netstat -c
Find the non supportive Address families in your system
# netstat --verbose
Display the kernel routing information
# netstat -r
Find out on which port a program is running
# netstat -ap | grep ssh
Find out which process is using a particular port
# netstat -an | grep ':80'
Show the list of network interfaces
# netstat -i
Display extended information on the interfaces
# netstat -ie
How to install SendMailAnalyser in linux, centOS?
SendmailAnalyzer can work in any platform where Sendmail and Perl could run. What you need is a modern Perl distribution 5.8.x or more is good but older version should also work.
Download sendmailanalyzer-x.x.tar.gz and perform the following opertaions
# tar -zxvf sendmailanalyzer-x.x.tar.gz
# cd sendmailanalyzer-x.x/
# perl Makefile.PL
# make && make install
Start SendmailAnalyzer daemon:
# /usr/local/sendmailanalyzer/sendmailanalyzer -f
Add httpd configuratiosn for SendmailAnalyzer
Alias /sareport /usr/local/sendmailanalyzer/www
<Directory /usr/local/sendmailanalyzer/www>
Options ExecCGI
AddHandler cgi-script .cgi
DirectoryIndex sa_report.cgi
Order deny,allow
Deny from all
Allow from 127.0.0.1
Allow from ::1
# Allow from .example.com
</Directory>
Test:
http://server_ip_address/sareport
Additional tasks to be added in crontab
# SendmailAnalyzer log reporting daily cache
0 1 * * * /usr/local/sendmailanalyzer/sa_cache > /dev/null 2>&1
# On huge MTA you may want to have five minutes caching
#*/5 * * * * /usr/local/sendmailanalyzer/sa_cache -a > /dev/null 2>&1
Logrotate:
/etc/logrotate.d/syslog to restart SendmailAnalyzer when maillog is rotated or create a cron job.
For example:
/var/log/cron /var/log/debug /var/log/maillog /var/log/messages /var/log/secure /var/log/spooler /var/log/syslog
{
sharedscripts
postrotate
/bin/kill -HUP `cat /var/run/syslogd.pid 2>/dev/null` 2>/dev/null || true
/PATH_TO/rc.sendmailanalyzer restart >/dev/null 2>&1 || true
# or /etc/rc.d/init.d/sendmailanalyzer restart >/dev/null 2>&1 || true
endscript
}
Download sendmailanalyzer-x.x.tar.gz and perform the following opertaions
# tar -zxvf sendmailanalyzer-x.x.tar.gz
# cd sendmailanalyzer-x.x/
# perl Makefile.PL
# make && make install
Start SendmailAnalyzer daemon:
# /usr/local/sendmailanalyzer/sendmailanalyzer -f
Add httpd configuratiosn for SendmailAnalyzer
Alias /sareport /usr/local/sendmailanalyzer/www
<Directory /usr/local/sendmailanalyzer/www>
Options ExecCGI
AddHandler cgi-script .cgi
DirectoryIndex sa_report.cgi
Order deny,allow
Deny from all
Allow from 127.0.0.1
Allow from ::1
# Allow from .example.com
</Directory>
Test:
http://server_ip_address/sareport
Additional tasks to be added in crontab
# SendmailAnalyzer log reporting daily cache
0 1 * * * /usr/local/sendmailanalyzer/sa_cache > /dev/null 2>&1
# On huge MTA you may want to have five minutes caching
#*/5 * * * * /usr/local/sendmailanalyzer/sa_cache -a > /dev/null 2>&1
Logrotate:
/etc/logrotate.d/syslog to restart SendmailAnalyzer when maillog is rotated or create a cron job.
For example:
/var/log/cron /var/log/debug /var/log/maillog /var/log/messages /var/log/secure /var/log/spooler /var/log/syslog
{
sharedscripts
postrotate
/bin/kill -HUP `cat /var/run/syslogd.pid 2>/dev/null` 2>/dev/null || true
/PATH_TO/rc.sendmailanalyzer restart >/dev/null 2>&1 || true
# or /etc/rc.d/init.d/sendmailanalyzer restart >/dev/null 2>&1 || true
endscript
}
How to install darkstat in linux, centOS?
Darkstat - Web Based Network Traffic & Bandwidth Monitoring Tool on Linux
# yum install darkstat
# darkstat -i eth0
Test:
http://ip-address:667
# yum install darkstat
# darkstat -i eth0
Test:
http://ip-address:667
How to install Monitorix in linux, centOS?
-->Monitorix is a lightweight system monitoring tool that can track services and resources of a system. This is one of the best tool to track system activities in simple and easiest way.
It can monitor system attributes like
-->System load
-->Active processes
-->Memory allocation
-->Kernel usage
-->Context switches and forks
-->VFS usage
-->Kernel usage per processor
-->Filesystems usage
-->Disk I/O activity
-->Inode usage
-->Time spent in I/O activity
-->Network traffic and usage
-->IPv4 states
-->IPv6 states
-->Active close
-->Passive close
-->UDP statistics
-->System services demand
-->IMAP and POP3 services
-->SMTP service
-->Network port traffic (Ports: 21, 22, 25, 80, 110, 139, 3306, 53, 143)
-->Users using the system
-->Devices interrupt activity
Installation Procedure
# yum install httpd rrdtool rrdtool-perl perl-libwww-perl perl-MailTools perl-MIME-Lite perl-CGI perl-DBI
Note: Some times on updated package this may not be enough, use the following command to update and download more packages to support the configurations.
# yum -y install rrdtool rrdtool-perl perl-libwww-perl perl-MailTools perl-MIME-Lite perl-CGI perl-DBI perl-XML-Simple perl-Config-General perl-HTTP-Server-Simple perl-IO-Socket-SSL
Download monitorix and install
# rpm -ivh http://www.monitorix.org/monitorix-n.n.n-1.noarch.rpm
After successful installations
# service monitorix start
#chkconfig monitorix on ----> Add to startup
Log file: /var/log/monitorix
Testing:
http://ip-address:8080/monitorix/
Thats all, comments and suggestions are welcome!!
It can monitor system attributes like
-->System load
-->Active processes
-->Memory allocation
-->Kernel usage
-->Context switches and forks
-->VFS usage
-->Kernel usage per processor
-->Filesystems usage
-->Disk I/O activity
-->Inode usage
-->Time spent in I/O activity
-->Network traffic and usage
-->IPv4 states
-->IPv6 states
-->Active close
-->Passive close
-->UDP statistics
-->System services demand
-->IMAP and POP3 services
-->SMTP service
-->Network port traffic (Ports: 21, 22, 25, 80, 110, 139, 3306, 53, 143)
-->Users using the system
-->Devices interrupt activity
Installation Procedure
# yum install httpd rrdtool rrdtool-perl perl-libwww-perl perl-MailTools perl-MIME-Lite perl-CGI perl-DBI
Note: Some times on updated package this may not be enough, use the following command to update and download more packages to support the configurations.
# yum -y install rrdtool rrdtool-perl perl-libwww-perl perl-MailTools perl-MIME-Lite perl-CGI perl-DBI perl-XML-Simple perl-Config-General perl-HTTP-Server-Simple perl-IO-Socket-SSL
Download monitorix and install
# rpm -ivh http://www.monitorix.org/monitorix-n.n.n-1.noarch.rpm
After successful installations
# service monitorix start
#chkconfig monitorix on ----> Add to startup
Log file: /var/log/monitorix
Testing:
http://ip-address:8080/monitorix/
Thats all, comments and suggestions are welcome!!
Download whole website using command
# wget -r --level=0 -convert-links --page-requisites --no-parent www.website.com
The wget options:
-r
--recursive, perform recursive
-l
--level=,Use 0 for infinite depth level or use number greater than 0 for limited depth.
-k
-convert-links,Modify links inside downloaded files to point to local files.
-p
--page-requisites, Get all images, css, js files which make up the web page.
-np
--no-parent, Don't download parent directory contents.
The wget options:
-r
--recursive, perform recursive
-l
--level=,Use 0 for infinite depth level or use number greater than 0 for limited depth.
-k
-convert-links,Modify links inside downloaded files to point to local files.
-p
--page-requisites, Get all images, css, js files which make up the web page.
-np
--no-parent, Don't download parent directory contents.
Install Cacti in Linux
Cacti is a complete frontend to RRDTool, it stores all of the necessary information to create graphs and populate them with data in a MySQL database.
We need to install the following software to install cacti.
1) MySQL Server : Store cacti data
2) NET-SNMP server – SNMP (Simple Network Management Protocol) is a protocol used for network management.
3) PHP with net-snmp module – Access SNMP data using PHP.
4) Apache / lighttpd / ngnix webserver : Web server to display graphs created with PHP and RRDTOOL.
Install the software
# yum install mysql-server mysql php-mysql php-pear php-common php-gd php-devel php php-mbstring php-cli php-snmp php-pear-Net-SMTP php-mysql httpd
Configure MySQL server
Setting up root password:-
# mysqladmin -u root password NEWPASSWORD
Create cacti MySQL database
# mysql -u root -p -e ‘create database cacti’
Create a user name cacti with a password your password, then enter
Login to mysql
# mysql -u root –p
mysql> GRANT ALL ON cacti.* TO cacti@localhost IDENTIFIED BY ‘your password’;
mysql> FLUSH privileges;
mysql> \q
Intall snmpd
Type the following command to install net-snmpd
# yum install net-snmp-utils php-snmp net-snmp-libs
To configure snmpd, open the snmpd.conf configuration file.
# vi /etc/snmp/snmpd.conf and modify like the following
com2sec local localhost public
group MyRWGroup v1 local
group MyRWGroup v2c local
group MyRWGroup usm local
view all included .1 80
access MyRWGroup “” any noauth exact all all none
syslocation Unknown (edit /etc/snmp/snmpd.conf)
syscontact Root (configure /etc/snmp/snmp.local.conf)
pass .1.3.6.1.4.1.4413.4.1 /usr/bin/ucd5820stat
Save and closed the configuration file and start the snmp service. Type the following.
# /etc/init.d/snmpd start
# chkconfig snmpd on
Install cacti
Update the repository:
rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
# yum install cacti
Install cacti tables
Type the following command to find out cacti.sql path:
# rpm -ql cacti | grep cacti.sql
Sample output:
/usr/share/doc/cacti-0.8.7d/cacti.sql
Type the following command to install cacti tables, use cacti user and password
# mysql -u cacti -p cacti < /usr/share/doc/cacti-0.8.7d/cacti.sql
Configure cacti database string, Open /var/www/cacti/include
# config.php
Modify the following changes as follows
/* make sure these values refect your actual database/host/user/password */
$database_type = “mysql”;
$database_default = “cacti”;
$database_hostname = “localhost”;
$database_username = “cacti”;
$database_password = “your password”;
$database_port = “3306″;
Configure httpd for cacti, Update allow from line, set to your LAN subnet to allow access to cacti
Open /etc/httpd/conf.d/cacti.conf file
# vi /etc/httpd/conf.d/cacti.conf
Alias /cacti/ /var/www/cacti/
<Directory /var/www/cacti/>
DirectoryIndex index.php
Options -Indexes
AllowOverride all
order deny,allow
allow from 172.16.0.0/16 #your network address
AddType application/x-httpd-php .php
php_flag magic_quotes_gpc on
php_flag track_vars on
</Directory>
Restart the httpd
# /etc/init.d/httpd restart
Setup cacti cronjob
Open /etc/cron.d/cacti file
# vi /etc/cron.d/cacti
Uncomment the line:
*/5 * * * * cacti /usr/bin/php /usr/share/cacti/poller.php > /dev/null 2>&1
Save and close the file.
Now cacti is ready, you can run the cacti type the following
http://server-IP-address/cacti/
or http://localhost/cacti
Note: The default username and password for cacti is admin / admin.
We need to install the following software to install cacti.
1) MySQL Server : Store cacti data
2) NET-SNMP server – SNMP (Simple Network Management Protocol) is a protocol used for network management.
3) PHP with net-snmp module – Access SNMP data using PHP.
4) Apache / lighttpd / ngnix webserver : Web server to display graphs created with PHP and RRDTOOL.
Install the software
# yum install mysql-server mysql php-mysql php-pear php-common php-gd php-devel php php-mbstring php-cli php-snmp php-pear-Net-SMTP php-mysql httpd
Configure MySQL server
Setting up root password:-
# mysqladmin -u root password NEWPASSWORD
Create cacti MySQL database
# mysql -u root -p -e ‘create database cacti’
Create a user name cacti with a password your password, then enter
Login to mysql
# mysql -u root –p
mysql> GRANT ALL ON cacti.* TO cacti@localhost IDENTIFIED BY ‘your password’;
mysql> FLUSH privileges;
mysql> \q
Intall snmpd
Type the following command to install net-snmpd
# yum install net-snmp-utils php-snmp net-snmp-libs
To configure snmpd, open the snmpd.conf configuration file.
# vi /etc/snmp/snmpd.conf and modify like the following
com2sec local localhost public
group MyRWGroup v1 local
group MyRWGroup v2c local
group MyRWGroup usm local
view all included .1 80
access MyRWGroup “” any noauth exact all all none
syslocation Unknown (edit /etc/snmp/snmpd.conf)
syscontact Root (configure /etc/snmp/snmp.local.conf)
pass .1.3.6.1.4.1.4413.4.1 /usr/bin/ucd5820stat
Save and closed the configuration file and start the snmp service. Type the following.
# /etc/init.d/snmpd start
# chkconfig snmpd on
Install cacti
Update the repository:
rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
# yum install cacti
Install cacti tables
Type the following command to find out cacti.sql path:
# rpm -ql cacti | grep cacti.sql
Sample output:
/usr/share/doc/cacti-0.8.7d/cacti.sql
Type the following command to install cacti tables, use cacti user and password
# mysql -u cacti -p cacti < /usr/share/doc/cacti-0.8.7d/cacti.sql
Configure cacti database string, Open /var/www/cacti/include
# config.php
Modify the following changes as follows
/* make sure these values refect your actual database/host/user/password */
$database_type = “mysql”;
$database_default = “cacti”;
$database_hostname = “localhost”;
$database_username = “cacti”;
$database_password = “your password”;
$database_port = “3306″;
Configure httpd for cacti, Update allow from line, set to your LAN subnet to allow access to cacti
Open /etc/httpd/conf.d/cacti.conf file
# vi /etc/httpd/conf.d/cacti.conf
Alias /cacti/ /var/www/cacti/
<Directory /var/www/cacti/>
DirectoryIndex index.php
Options -Indexes
AllowOverride all
order deny,allow
allow from 172.16.0.0/16 #your network address
AddType application/x-httpd-php .php
php_flag magic_quotes_gpc on
php_flag track_vars on
</Directory>
Restart the httpd
# /etc/init.d/httpd restart
Setup cacti cronjob
Open /etc/cron.d/cacti file
# vi /etc/cron.d/cacti
Uncomment the line:
*/5 * * * * cacti /usr/bin/php /usr/share/cacti/poller.php > /dev/null 2>&1
Save and close the file.
Now cacti is ready, you can run the cacti type the following
http://server-IP-address/cacti/
or http://localhost/cacti
Note: The default username and password for cacti is admin / admin.
Monitor Network Switch and Ports Using Nagios
1. Enable switch.cfg in nagios.cfg
Uncomment the switch.cfg line in /usr/local/nagios/etc/nagios.cfg as shown below.
cfg_file=/usr/local/nagios/etc/objects/switch.cfg
2. Add new hostgroup for switches in switch.cfg
Add the following switches hostgroup to the /usr/local/nagios/etc/objects/switch.cfg file.
define hostgroup
{
hostgroup_name switches
alias Network Switches
}
3. Add a new host for the switch to be monitered
In this example, I’ve defined a host to monitor the core switch in the /usr/local/nagios/etc/objects/switch.cfg file. Change the address directive to your switch ip-address accordingly.
define host
{
use generic-switch
host_name core-switch
alias Cisco Core Switch
address 192.168.1.50
hostgroups switches
}
4. Add common services for all switches
Displaying the uptime of the switch and verifying whether switch is alive are common services for all switches. So, define these services under the switches hostgroup_name as shown below.
# Service definition to ping the switch using check_ping
define service
{
use generic-service
hostgroup_name switches
service_description PING
check_command check_ping!200.0,20%!600.0,60%
normal_check_interval 5
retry_check_interval 1
}
# Service definition to monitor switch uptime using check_snmp
define service
{
use generic-service
hostgroup_name switches
service_description Uptime
check_command check_snmp!-C public -o sysUpTime.0
}
5. Add service to monitor port bandwidth usage
check_local_mrtgtraf uses the Multil Router Traffic Grapher – MRTG. So, you need to install MRTG for this to work properly. The *.log file mentioned below should point to the MRTG log file on your system.
define service
{
use generic-service
host_name core-switch
service_description Port 1 Bandwidth Usage
check_command check_local_mrtgtraf!/var/lib/mrtg/192.168.1.11_1.log!AVG!1000000,2000000!5000000,5000000!10
}
6. Add service to monitor an active switch port
Use check_snmp to monitor the specific port as shown below. The following two services monitors port#1 and port#5. To add additional ports, change the value ifOperStatus.n accordingly. i.e n defines the port#.
# Monitor status of port number 1 on the Cisco core switch
define service
{
use generic-service
host_name core-switch
service_description Port 1 Link Status
check_command check_snmp!-C public -o ifOperStatus.1 -r 1 -m RFC1213-MIB
}
# Monitor status of port number 5 on the Cisco core switch
define service
{
use generic-service
host_name core-switch
service_description Port 5 Link Status
check_command check_snmp!-C public -o ifOperStatus.5 -r 1 -m RFC1213-MIB
}
7. Add services to monitor multiple switch ports together
Sometimes you may need to monitor the status of multiple ports combined together. i.e Nagios should send you an alert, even if one of the port is down. In this case, define the following service to monitor multiple ports.
# Monitor ports 1 - 6 on the Cisco core switch.
define service
{
use generic-service
host_name core-switch
service_description Ports 1-6 Link Status
check_command check_snmp!-C public -o ifOperStatus.1 -r 1 -m RFC1213-MIB, -o ifOperStatus.2 -r 1 -m RFC1213-MIB, -o ifOperStatus.3 -r 1 -m RFC1213-MIB, -o ifOperStatus.4 -r 1 -m RFC1213-MIB, -o ifOperStatus.5 -r 1 -m RFC1213-MIB, -o ifOperStatus.6 -r 1 -m RFC1213-MIB
}
8. Validate configuration and restart nagios
Verify the nagios configuration to make sure there are no warnings and errors.
# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Total Warnings: 0
Total Errors: 0
Things look okay - No serious problems were detected during the pre-flight check
Restart the nagios server to start monitoring the VPN device.
# /etc/rc.d/init.d/nagios stop
Stopping nagios: .done.
# /etc/rc.d/init.d/nagios start
Starting nagios: done.
Check: http://Your-server-ip/nagios or http://localhost/nagios in browsers
Network Related Commands
# dhclient eth0
active interface 'eth0' in dhcp mode
# ethtool eth0
show network statistics of eth0
# host www.example.com
lookup hostname to resolve name to ip address and viceversa
# hostname
show hostname of system
# ifconfig eth0
show configuration of an ethernet network card
# ifconfig eth0 192.168.1.1 netmask 255.255.255.0
configure IP Address
# ifconfig eth0 promisc
configure 'eth0' in promiscuous mode to gather packets (sniffing)
# ifdown eth0
disable an interface 'eth0'
# ifup eth0
activate an interface 'eth0'
# ip link show
show link status of all network interfaces
# iwconfig eth1
show wireless networks
# iwlist scan
wifi scanning to display the wireless connections available
# mii-tool eth0
show link status of 'eth0'
# netstat -tup
show all active network connections and their PID
# netstat -tupl
show all network services listening on the system and their PID
# netstat -rn
show routing table alike "route -n"
# nslookup www.example.com
lookup hostname to resolve name to ip address and viceversa
# route -n
show routing table
# route add -net 0/0 gw IP_Gateway
configure default gateway
# route add -net 192.168.0.0 netmask 255.255.0.0 gw 192.168.1.1
configure static route to reach network '192.168.0.0/16'
# route del 0/0 gw IP_gateway
remove static route
# echo "1" > /proc/sys/net/ipv4/ip_forward
activate ip routing
# tcpdump tcp port 80
show all HTTP traffic
# whois www.example.com
lookup on Whois database
active interface 'eth0' in dhcp mode
# ethtool eth0
show network statistics of eth0
# host www.example.com
lookup hostname to resolve name to ip address and viceversa
# hostname
show hostname of system
# ifconfig eth0
show configuration of an ethernet network card
# ifconfig eth0 192.168.1.1 netmask 255.255.255.0
configure IP Address
# ifconfig eth0 promisc
configure 'eth0' in promiscuous mode to gather packets (sniffing)
# ifdown eth0
disable an interface 'eth0'
# ifup eth0
activate an interface 'eth0'
# ip link show
show link status of all network interfaces
# iwconfig eth1
show wireless networks
# iwlist scan
wifi scanning to display the wireless connections available
# mii-tool eth0
show link status of 'eth0'
# netstat -tup
show all active network connections and their PID
# netstat -tupl
show all network services listening on the system and their PID
# netstat -rn
show routing table alike "route -n"
# nslookup www.example.com
lookup hostname to resolve name to ip address and viceversa
# route -n
show routing table
# route add -net 0/0 gw IP_Gateway
configure default gateway
# route add -net 192.168.0.0 netmask 255.255.0.0 gw 192.168.1.1
configure static route to reach network '192.168.0.0/16'
# route del 0/0 gw IP_gateway
remove static route
# echo "1" > /proc/sys/net/ipv4/ip_forward
activate ip routing
# tcpdump tcp port 80
show all HTTP traffic
# whois www.example.com
lookup on Whois database
User and Group Related Commands
# chage -E 2005-12-31 user1
set deadline for user password
# groupadd [group-name]
create a new group
# groupdel [group-name]
delete a group
# groupmod -n moon sun
rename a group from moon to sun
# grpck
check correct syntax and file format of '/etc/group' and groups existence
# newgrp - [group-name]
log into a new group to change default group of newly created files
# passwd
change password
# passwd user1
change a user password (only by root)
# pwck
check correct syntax and file format of '/etc/passwd' and users existence
# useradd -c "User Linux" -g admin -d /home/user1 -s /bin/bash user1
create a new user "user1" belongs "admin" group
# useradd user1
create a new user
# userdel -r user1
delete a user ( '-r' eliminates home directory)
# usermod -c "User FTP" -g system -d /ftp/user1 -s /bin/nologin user1
change user attributes
set deadline for user password
# groupadd [group-name]
create a new group
# groupdel [group-name]
delete a group
# groupmod -n moon sun
rename a group from moon to sun
# grpck
check correct syntax and file format of '/etc/group' and groups existence
# newgrp - [group-name]
log into a new group to change default group of newly created files
# passwd
change password
# passwd user1
change a user password (only by root)
# pwck
check correct syntax and file format of '/etc/passwd' and users existence
# useradd -c "User Linux" -g admin -d /home/user1 -s /bin/bash user1
create a new user "user1" belongs "admin" group
# useradd user1
create a new user
# userdel -r user1
delete a user ( '-r' eliminates home directory)
# usermod -c "User FTP" -g system -d /ftp/user1 -s /bin/nologin user1
change user attributes
ls commands
See list SCSI devices (or hosts) and their attributes under Linux operating systems
# lsscsi -g
Use this command to list block devices
# lsblk
To see file system type
# lsblk -f
To output info about permissions
# lsblk -m
Use this command to see Linux distribution-specific information, enter
# lsb_release
# lsb_release -a
Use this command to see USB buses in the Linux based system and the devices connected to them
# lsusb
lscpu command shows information about CPU architecture information like number of CPUs, threads, cores
# lscpu
lspci command shows information about PCI buses in the system and devices connected
# lspci
lspci command can be used to find out if a given PCI hardware
# lspci | grep VT6120
lshw command finds detailed information about the hardware configuration
# lshw / lshw-gtk
Use ls command to list directory contents
# ls
# ls -l ## long format
# ls -F ## appends a character revealing the nature of a file
# ls -a ## Show all files including hidden files
# ls -R ## recursively lists subdirectories
# ls -d ## Get info about a symbolic link or directory
# ls -t ## Sort the list of files by modification time
# ls -h ## Show sizes in human readable format
# ls -B ## In directories, ignore files that end with ‘~’ (backup files)
# ls -Z ## Display the SELinux security context
# ls --group-directories-first -l ## Show directories first (group directories). Useful on server.
# ls --color ## Colorize the # ls output
# ls --hide='*.txt' -l ## Hide or ignore files whose names ends with .txt
Use this command list open files, network ports, active process
#lsof | less
List all open file
#lsof -u vivek -i
See all files opened by user "vivek"
#lsof -i 4 -a -p 7007
List all open IPv4 network files in use by the process whose PID is 7007
#lsof -i TCP80
Find process running on tcp port 80
#lsof -i 6
List only open IPv6 network files
#lsof -i 4
List only open IPv4 network files
#lsof -i TCP1-1024
List process open in port range 1 to 1024
#lsof -i @server.host.example1200-1205
List all files using any protocol on ports 1200 to 1205 of host server.host.example, use
#lsof /dev/sr0
List all open files on device /dev/sr0
#lsof /dev/dvd
Find out why my DVD drive does not eject?
#lsof -i -u^root
See all files open by all users except root
#lsof /etc/foobar
Find out who's looking at the /etc/foobar file?
Use lsattr to lists the file attributes on a second extended file system
# lsattr /etc/passwd
Use lshal command to display items in the HAL (Hardware Abstraction Layer)
# lshal | less
Use this command to show the content of given initramfs images
# lsinitramfs /boot/initrd.img
Use this command to list all device driver loaded currently in the Linux Kernel
# lsmod
See information about the PCMCIA sockets and devices
# lspcmcia
Use this command to to lists all locks associated with the local files of the system
# lslk
Use this command to display the number of messages in a mailbox
# lsmbox
# lsscsi -g
Use this command to list block devices
# lsblk
To see file system type
# lsblk -f
To output info about permissions
# lsblk -m
Use this command to see Linux distribution-specific information, enter
# lsb_release
# lsb_release -a
Use this command to see USB buses in the Linux based system and the devices connected to them
# lsusb
lscpu command shows information about CPU architecture information like number of CPUs, threads, cores
# lscpu
lspci command shows information about PCI buses in the system and devices connected
# lspci
lspci command can be used to find out if a given PCI hardware
# lspci | grep VT6120
lshw command finds detailed information about the hardware configuration
# lshw / lshw-gtk
Use ls command to list directory contents
# ls
# ls -l ## long format
# ls -F ## appends a character revealing the nature of a file
# ls -a ## Show all files including hidden files
# ls -R ## recursively lists subdirectories
# ls -d ## Get info about a symbolic link or directory
# ls -t ## Sort the list of files by modification time
# ls -h ## Show sizes in human readable format
# ls -B ## In directories, ignore files that end with ‘~’ (backup files)
# ls -Z ## Display the SELinux security context
# ls --group-directories-first -l ## Show directories first (group directories). Useful on server.
# ls --color ## Colorize the # ls output
# ls --hide='*.txt' -l ## Hide or ignore files whose names ends with .txt
Use this command list open files, network ports, active process
#lsof | less
List all open file
#lsof -u vivek -i
See all files opened by user "vivek"
#lsof -i 4 -a -p 7007
List all open IPv4 network files in use by the process whose PID is 7007
#lsof -i TCP80
Find process running on tcp port 80
#lsof -i 6
List only open IPv6 network files
#lsof -i 4
List only open IPv4 network files
#lsof -i TCP1-1024
List process open in port range 1 to 1024
#lsof -i @server.host.example1200-1205
List all files using any protocol on ports 1200 to 1205 of host server.host.example, use
#lsof /dev/sr0
List all open files on device /dev/sr0
#lsof /dev/dvd
Find out why my DVD drive does not eject?
#lsof -i -u^root
See all files open by all users except root
#lsof /etc/foobar
Find out who's looking at the /etc/foobar file?
Use lsattr to lists the file attributes on a second extended file system
# lsattr /etc/passwd
Use lshal command to display items in the HAL (Hardware Abstraction Layer)
# lshal | less
Use this command to show the content of given initramfs images
# lsinitramfs /boot/initrd.img
Use this command to list all device driver loaded currently in the Linux Kernel
# lsmod
See information about the PCMCIA sockets and devices
# lspcmcia
Use this command to to lists all locks associated with the local files of the system
# lslk
Use this command to display the number of messages in a mailbox
# lsmbox
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