sudo mount -n -o remount,rw /

The post Configuring NFS to access the files from remote Linux machine as a mount point appeared first on scmGalaxy.

The post Linux User Management appeared first on scmGalaxy.

You can find the memory used by a program (process) by looking into /proc directory or using standard command such as ps or top.

The post 20 pmap Commands Examples in Linux / UNIX | pmap Commands Tutorial appeared first on scmGalaxy.

If a linux-build-server suddenly starts getting slow, I would divide my approach / troubleshooting into 3 section as follows;

1. System Level troubleshooting

a. RAM related issues

b. Disk Space related Issues

c. Disk I/O read write issues

d. Network Hardware issues

e. Mount issues

f. Too Many process running in the machine

2. Application Level troubleshooting

a. Application is not behaving properly. Hit to Application log file OR application server log file OR web server Log file and try to understand the issues.

b. zombie process issues – Find out if any as such process which is causing the system performance issues.

c. Application Log – depends on the application installed, this can be referred and make use of the experience with the project and troubleshoot.

d. Web Server Log – we can check http, tomcat log as well.

e. Application Server Log – We can see jboss, weblogic logs to see if the application server response/receive time is the issues for slowness.

f. Memory Leak of any application – This is one of well known issues in lunux based server due to bad application coding. Many times this can be resolved either by fixing the code or rebooting. But many other solutions are there to apply.

3. Dependent Services troubleshooting

a. SMTP Response time – SMTP server is not responding faster which is causing delay in response and queue up many processes.

b. Network issues – There are many System performance issues is dependent on network or service which is depends on the network.

c. Firewall related issues

d. Antivirus related issues

 Some of the useful commands for troubleshooting are..

1. df –k

2. du –sh

3. top

4. uptime

5. ps –eaf | grep

6. vmstat

7. ping

8. tail –f <logfile>

9. iostat

10.free

11.kill -9

12.mount

13.sar

14.ifconfig eth0 | enable | disable

15.traceroute

16.netstat -r

17.nslookup

18.route

   There are various options available for each commands and depends on the need during the troubleshooting, right commands can be applied. To find arguments and their explanation, I usually refer google.com rather than man page.

The post If a linux-build-server suddenly starts getting slow, what would you check? appeared first on scmGalaxy.

su: Acquiring Superuser Status
# su  :- Acquire  Superuser after entering password but home directory does not change
# su – l :– Acquire Superuser access after password but home  directory change to ROOT
# su  – henry : – To  Login and Recreate a user environment
# sudo -s root -c “/bin/bash -l”

passwd – Changing any Password
# passwd henry
stat <fileName>

ulimit – Setting Limits on file size
ulimit command impost a restriction on the maximum size of a file that a user is permitted to create
# ulimit 20971510                             This is often placed in /etc/profile. Measured in 512 byte blocks

umask – Please refer user manual

Source
The source command in shell is used to execute commands from a file in the current shell. This is useful to load function or variables stored in another file.
# source filename
# source /path/to/file

locate

To locate any files in system. This works based on updatedb.

# locate

# updatedb     Run as a root.File location is /var/lib/mlocate/mlocate.db

which
shows the full path of (shell) commands

od
od command dumps a file in octal, decimal, and other formats.

# od -c special-chars.txt

# od -bc special-chars.txt

chkconfig
chkconfig command is used to setup, view, or change services that are configured to start automatically during the system startup.

The –list option displays all the services with the current startup configuration status.
# chkconfig –list
To view only the services that are configured to be started during system startup, do the following. Please note that this assumes that your system startup level is 3
# chkconfig –list | grep 3:on
To display the current settings for a selected service only, use chkconfig –list followed by the name of the service:
# chkconfig –list service_name

To enable a service in runlevels 2, 3, 4, and 5, type the following at a shell prompt as root.
# chkconfig service_name on
To disable a service in runlevels 2, 3, 4, and 5, type the following at a shell prompt as root.
# chkconfig service_name off

# chkconfig network –level 3 && echo “Network service is configured for level 3”
# chkconfig network –level 1 && echo “Network service is configured for level 1”

To view the startup configuration of a particular service, grep the output of ‘chkconfig –list’ for that service.
# chkconfig –list | grep network

Add a new Service to the Startup
# chkconfig –add iptables

To remove it from the startup list, use the –del option as shown below.
# chkconfig –del ip6tables

How to install services?

Step 1. Copy the script into /etc/init.d/ such as /etc/init.d/httpd

Step 2. chkconfig --add httpd

http://bitnami.org/article/how-to-install-services-on-linux

service
# service network restart
OR
# /etc/init.d/network restart

To start Linux network service:
# service network start

To stop Linux network service:
# service network stop

date – Setting the system Date
# date MMDDhhmm

groupadd
# groupadd –g 241 dba               The command place entry in /etc/group which can also insert manually(dba:x:241). 241 is GID of dba

useradd
# useradd –u 210 –g dba –c “The RDBMS” –d /home/oracle –s /bin/bash –m username

usermod
# usermod –s /bin/csh username

userdel
# userdel username

shutdown
# shutdown 17:30                         Shutdown at 17:30
# shutdown –r now                     Shutdown immediately and reboot
# shutown –r 17:30                      Shutdown immediately and reboot at 17:30
# shutown –h now                       Shutdown immediately and halt
# shutown –h 17:30                     Shutdown at 17:30
# shutdown –c                               Cancel the shutdown
Reboot / Poweroff / halt

df
The df (disk free) command lets you see if file systems are full.

• To see how much free space is in all file systems (including mounted ones), use df
• To see how much free space is in all file systems with names containing “dev”, use df | grep dev
• To see how much free space is in your home file system, use df /home
• To see how much free space is in the file system “tmp”, use df /tmp
• To see if there is enough free space on the machine, check the output from the following

# df /usr,
# df /var
# df -k /tmp /home                                          -k Reports in units of KB
# df –h / /usr                                                       -h reports in MB, GB

du -Disk usage
# du  /home/sales/tml
# du –s /home/*                                               -s options for summary disk usage information for tml directory
# du –sh /home                                                 -h options for reports in MB , GB
# find /home –size +1024 –print                                     Files above 1MB
# find /home –size +1024 –size -4096 – print             Files above 1Mb and below 4MB

mount / unmount

Using file for incremental Backup
# tar –cvf /dev/rct0 `find /home –type f –newer .last_time –print`
# touch .last_time
# tar –cvf /dev/rct0 /home > homelist `date “+%d%b%y”`

xrags

xargs vs. exec {}

Remote machine Login: telnet, rlogin
telnet
rlogin

Secure Login with password: ssh
ssh

Remote login without Password: rsh
rsh

File Transfer: ftp, rcp, scp
rcp

scp

ftp
ftp rajesh-servers – How to Login
Directory Commands:
# cd [directory] Changes to the specified directory on the remote system.
# dir Displays a long listing of files on the remote system.
# ls Displays a short listing of the files on the remote system.
# lcd Changes the working directory on the local system.
# pwd Displays the working directory on the remote system.
File Transfer Commands:
# get [filename] Downloads a single file from the remote system.
# put [filename] Uploads a single file to the remote system.
# mget [file…] Downloads multiple files from the remote system.
# mput [file…] Uploads multiple files to the remote system.

Generic troubleshooting tips

• Use tail –f to watch log file in real time, advantage is simple you can spot error or warning message in real time.
  tail –f /path/to/log/file
  Example(s):
  # tail –f /var/log/maillog
• Use telnet command to see if you get response or not. Sometime you will also see some informative message:
  telnet ip port

Example(s):
# telnet localhost 53
# telnet localhost 25

• Make sure you can see PID of your service.
  pidof service-name
  cat /var/run/service.pid
  Example(s):
  # pidof sshd
  # cat /var/run/sshd.pid
• You need to make sure that your DNS server or third party DNS server (ISP) is accessible. This is an important step, as many network services depend upon DNS; especially sendmail/postfix or Squid etc for example. Run dig or nslookup. No timeout should occurred.
  
  # dig your-domain.com
  # nslookup gw.isp.com
  # more /etc/resolv.conf

Performance /  Memory / CPU / Process check
ps – Read user manual

w username –  Find Out Who Is Logged on And What They Are Doing. w command displays information about the users currently on the machine, and their processes.

top
The top program provides a dynamic real-time view of a running system i.e. actual process activity. By default, it displays the most CPU-intensive tasks running on the server and updates the list every five seconds.

uptime
tell How Long The System Has Been Running

free – Memory Usage
The command free displays the total amount of free and used physical and swap memory in the system, as well as the buffers used by the kernel.
# free –m                                                            Display free memory size in MB
# free -t –m                                                        Displays a line containing the totals memory in MB

vmstat

Linux Performance Monitoring using iostat, mpstat and vmstat

iostat

pmap

mpstat 

# strace & truss – Debug the Execution of a Program in Linux
Trace the Execution of an Executable
# strace ls

Save the Trace Execution to a File Using Option -o
strace -o output.txt ls

Execute Strace on a Running Linux Process Using Option -p
# ps -C firefox-bin To get the process id
# sudo strace -p 1725 -o firefox_trace.txt

Print Relative Time for System Calls Using Option -r
# strace -r ls

Networking troubleshooting tips

Hostname verification or setup tools

• hostname : To get hostname of server.
• hostname –s : To get FQDN hostname of server
• more /etc/sysconfig/network : To setup hostname and networking can enable or disabled.
• dnsdomainname : List or setup domainname.
• more /etc/hosts : Make sure at least localhost entry do exist.

Ethernet configuration tools

service network reload|restart|stop|start : To reload (after changed made in ip config file)|restart|stop|start network interface with all properties.

route
The route command allows you to add static routes to the routing tabling.

traceroute (tracert in Windows)
Traceroute displays the routers that are passed through to reach the destination.

dmesg
When the system boots up, it prints number of messages on the screen that displays information about the hardware devices that the kernel detects during boot process.
These messages are available in kernel ring buffer and whenever the new message comes the old message gets overwritten. You could see all those messages after the system bootup using the dmesg command.

# dmesg | more

# dmesg | grep Memory

# dmesg  | grep eth

ifconfig
The ifconfig command is used to display the local interface configuration (winipcfg for Windows) and to modify the configuration.
ifconfig eth0 up|down : To enable|disable network interface

netstat
The network status command netstat displays status information about the network interfaces on the host machine. Netstat command displays the network related information such as network connections, routing tables, interface statistics.
-a                Show both listening and non-listening sockets
-n                prints the numeric forms of IP address

# netstat -ain                                  Local interface status
# netstat -rn                                    Routing table information
# netstat –an                                  Display Active Internet Connections and domain sockets using netstat
# netstat -tap                                 Display Active Connections with Process ID and Program Name
# netstat –-route                          Display Routing Table
# netstat –statistics –raw         Display RAW network statistics
# netstat –tcp –numeric           List of TCP connection to and from the machine.
netstat -tuplin                                UNIX

iptables

To know which ports are running in the machine.
ping
The ping command allows you to determine that the:

• TCP/IP stack is configured properly
• Network interface card is configured properly
• Default gateway and subnet mask is configured properly
• Domain name services is configured properly.

# ping ipaddress to check if the ip address in connected with network and if host is alive or dead
# ping 127.0.0.1/localhost – to check TCP/IP services is running properly or not. Checks that your TCP/IP stack is working properly up to the NIC. If this fails, check to see if you have TCP/IP services loaded.
# ping “IP address of default gateway” – Checks that the NIC is working on the local subnet by pinging the local side of the default gateway which is a router. If this fails, check that TCP/IP is bound to the NIC. Then check that the NIC’s IRQ, and base address are set properly both on the card itself and in the operating system’s interface configuration.
# ping “domain name” if DNS name is correctly configured. If it fails, check that the DNS server’s IP address is entered in properly in the TCP/IP configuration.

arp

address resolution protocol

# arp   – To see the IP to MAC address translation table
# arp -a  -Use this command to see the IP to MAC address translation table if you are having problems connecting to other network hosts. It is a dynamic cache which updates every 120 seconds.

# more /etc/modules.conf : To see your network card configuration alias for eth0 exists or not.
# lsmod : To list loaded modules (read as drivers), here you need to see that eth0 module is loaded or not, if not loaded then use insmod to insert (load) driver.
# dhclient : Dynamic Host Configuration Protocol Client, run this if your Ethernet card is not getting ip from DHCP box on startup; this command does by default shows useful information.

To see if service blocked because of access control
# iptables –n –L : To list all iptable rules; useful to see if firewall blocks service or not.
# service iptables stop|start : To start|stop iptables
# more /etc/xinetd.conf

sar
sar is an excellent monitoring tool that displays performance data of pretty much every resource of the system including CPU, memory, IO, paging, networking, interrupts etc., Sar Collects, Reports (displays) and Saves the performance data.

# sar –u | more         Display CPU Statistics using Sar Command
# sar –d | more         Display Disk IO Statistics using sar command
# sar -n DEV | more Display networking Statistics using sar command
# sar -n SOCK |more Display networking Statistics using sar command
# sar -n DEV -f /var/log/sa/sa24 | more   To display the network counters from the 24th
# sar 4 5                                             You can also display real time usage using sar

lsof
lsof stands for “ls open files”, which will list all the open files in the system. The open files include network connection, devices and directories. The output of the lsof command will have the following columns:

COMMAND process name.
PID process ID
USER Username
FD file descriptor
TYPE node type of the file
DEVICE device number
SIZE file size
NODE node number
NAME full path of the file name.

# lsof | more              View all open files of the system
# lsof | wc -l                How many files are open in the system at any given point
# lsof –u ramesh       View open files by a specific user. A system administrator can use this command to get some idea on what users are executing on the system.
# lsof /bin/vi               it displays all users who are currently using vi

Some external Tools
iptraf – Real-time Network Statistics
tcpdump  – Detailed Network Traffic Analysis
Nagios – Server And Network Monitoring
Cacti – Web-based Monitoring Tool
KDE System Guard – Real-time Systems Reporting and Graphing
Gnome System Monitor – Real-time Systems Reporting and Graphing
nmap – scan your server for open ports.
lsof – list open files, network connections and much more.
ntop web based tool – ntop is the best tool to see network usage in a way similar to what top command does for processes i.e. it is network traffic monitoring software. You can see network status, protocol wise distribution of traffic for UDP, TCP, DNS, HTTP and other protocols.
Conky – Another good monitoring tool for the X Window System. It is highly configurable and is able to monitor many system variables including the status of the CPU, memory, swap space, disk storage,
temperatures, processes, network interfaces, battery power, system messages, e-mail inboxes etc.
GKrellM – It can be used to monitor the status of CPUs, main memory, hard disks, network interfaces, local and remote mailboxes, and many other things.
vnstat – vnStat is a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s).
htop – htop is an enhanced version of top, the interactive process viewer, which can display the list of processes in a tree form.
mtr – mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.

yum
Rsync
rpm – Refer Cheat Book

Some Well known System services
QUICK DNS Flush                             /etc/rc.d/init.d/nscd restart
/Proc file system – Various Kernel Statistics
# cat /proc/cpuinfo
# cat /proc/meminfo
# cat /proc/zoneinfo
# cat /proc/mounts

Questions
What is MASK in output of ifconfig
Understand the output of ifconfig in linux such as RX packets and TX packets
Set ip address using commands line

Change Host name in RHEL
Changes should be made in the following files.
/etc/hosts
/etc/sysconfig/network

For finding your java process
jps -v      For finding your java process.
jstack PID  To Get stack of threads inside jvm

If application running under different user than yourself
sudo jps -v
sudo jstack 6172

The post Linux Commands for Administrator | Linux Admin Commands Reference appeared first on scmGalaxy.

General Commands Not Used Frequently
cal – The Calender
bc – The Calculator
file – knowing the file types
cmp – Comparing two files.
comm – Common in two files
dos2unix and unix2dos – Converting between dos and unix
stat – Display file or file system status such as Access, Modify,Change, users and more
# stat <fileName> unix Command

General Commands Frequently Used
Script – recording your session
Passwd – change your password
Echo  – Displaying the message
Printf – Displaying the message
who – Who are the Users
who am I – To know my user name
uname – Knowing your machine characteristics
# uname –a  – To Print all info.
tty – knowing your terminal
pwd – Checking Current Directory
cd – changing the current Directory
mkdir – Making directories
rmdir – removing directories
ls – Listing Directory Contents
# ls –F – Marks executables with *, directories with / and symbolic links with @ at the end of file name.
# ls – a – Shows all filesnames including beginning with a dot.
# ls –R – Recursive display list of files and folders
# ls -1 – one filename in each line
# ls –l long listing + time of last file modification
# ls –t Sorts filenames by last modification time
# ls –u – Sorts filenames by last access time
# ls –I – Displays inode number
# ls –lc – Time of last inode modifcation

Cat – Displaying and creating Files
# cat filename – Displaying file contents
# cat –n filename – Displaying file contents with line numbers
# cat > filename – To Create a file name

More – Paging Output
# more filename – To to display the filename contents

Less – Paging Output

wc – Counting lines, Words and Characters
# -l – Option counts only the number of lines
# -w – Option counts only the words.
# -c – Options counts only the characters.

cp – copying a files
Options
# -p – Copy the files including preserve the mode, ownership and permissions.
# -R – Copying Directory Structure

gzip and gunzip – Compressing and Decompressing Files
# gzip filename
# gzip –l – To find out how much of the compression was archived.
# gzip –d filename – To Decompress a file
# gunzip filename – To Decompress a file
# gzip –R dir – To Compress Recursive

Tar – The archival Program
# -c – To create a archive
# -x – Extract files from archive
# -t – Display fils in archive
# -v – verbose
# -f – name of the arch filename .tar
# tar –cvf filename.tar filename1 filename2
# tar –xvf filename.tar

Create tar and gzip
# tar cvf – foodir | gzip > foo.tar.gz

Un-tar and gunzip
# tar -zxvf apache-activemq-5.1.0-bin.tar.gz

Un-tar and uncompress using gunzip
# gunzip -c apache-activemq-5.1.0-bin.tar.gz | tar xvf –
or alternatively:
# gunzip apache-activemq-5.1.0-bin.tar.gz | tar xvf –

File Attributes
chmod – Changing File Permission

Abbreviations Used by chmod

Example:
# chmod u+x filename
# chmod u+x filename
# chmod ugo+x filename
# chmod u+x filename1 filename2 filename3
# chmod a-x,go+r filename
# chmod 566 filename
# chmod 755 filename
# chmod –R 755 .
# chmod –R a+x *

Chown – Changing File Ownership
# chown username filename
More example needed.

Shell’s Wild-Cards

Ps – Process Status
Options to ps

Example
# ps -ef
# ps –u sumit
# ps –a
# ps –e
# ps -A – ps command will report a snapshot of the current processes. To select all processes use the -A
# ps -Al – Show Long Format Output
# ps -AlF – To turn on extra full mode (it will show command line arguments passed to process):
# ps axu – Print All Process On The Server
# ps -U vivek -u vivek u – See Every Process Running As User Vivek
# ps -p 55977 -o comm= – Display The Name of PID 55977
# ps -auxf | sort -nr -k 4 | head -10 – Find Out The Top 10 Memory Consuming Process
# ps -auxf | sort -nr -k 3 | head -10 – Find Out top 10 CPU Consuming Process

# $! – Store the PID of the last background jobs
# echo $$  – To Know the PID of current Shell
# echo $SHELL – To Know the Current Shell
# System process easily identifies the ? in the TTY coloumn.
# Mechanism of Process Creation
Fork
Exec
Wait

& and nohup – Ruunning jobs in background
# nohup sort emp.lst $

nice – Job execution with low priority
Kernel decides how much processor time is required for a process based on the nice value. Possible nice value range is: -20 to 20. A process that has a nice value of -20 is very high priority. The process that has a nice value of 20 is very low priority.
Use ps axl to display the nice value of all running process as shown below.
# ps axl
# nice command is used with & operator to reduce the priority of jobs
# nice script.sh &
# ./nice-test.sh &                             Default the nice value of 0
# nice -10 ./nice-test.sh &            Nice value is 10                 Low priority.
# nice –10 ./nice-test.sh &          Nice value is -10                High priority.

Kill – killing the process
# kill PID
# kill PID1 PID2 PID3
# kill $i – Killing the last background process
# kill –s KILL PID – recommended way for killing (SIGKILL)
# kill -9 PID – same as above but not recommended. (SIGKILL)
# kill -9 $$  -$$ store the PID of current shell
# kill –s KILL 0 – kill all the process including the login shell.
# kill –l – To View the list of all signal names and numbers that are available on your machine.
# kill %1 – Kill first background jobs

Jobs
List the background jobs in following fashion
[3] +       running                                command
[1] –        running                                command
[2]          running                                command

bg – Convert Jobs to background
# if you have invoked a command and the prompt has not yet return, you can suspend the job by pressing Ctrl-Z. Observe that job has not been terminated yet; its onl y suspended (“stopped”). Now you can use bg command to push the current foreground job in the background.
# bg %2 – Sends second job to background
# bg %sort – Sends sort job to background

fg – bring background job to foreground
# fg – To bring most recent job to forground
# fg %1 – Bring First job to foreground
# fg %2 – Bring second job to foreground
# fg %sort – Bring sort job to foreground

at – On time execution
# at 14:08
at > script.sh
[ctrl-d]

Batch – execute when system resources are available
# batch < script.sh

Cron – Schedule and run jobs periodically
# crontab –e – To Edit the cron tab
# crontab –l – To Display the cron tab
# crontab cron.tx – cron.txt contains cron commands
# crontab –r – To Remove the cron

Format of crontab – TODO

Customizing the environment

# set – set statemtent display a complete list of all environment variable
# PATH =$PATH:/usr/xpg4/bin – Adding new value to old values
# PS1 =”C> “ – To Change the prompt
# PS1=’[$PWD] ‘ – To Change the prompt to pwd
# alias cp=”cp –I” – To Set the alias in bash
# history – To See the history
# IFS – Field Separators for commands and arguments
# !! – Repeat Previous commands
# !2 – Repeat commands 2 from history output
# !-2 – Execute the commands prior to previous one
# !v – Execture very last commands beginning withg v
# $_ – Using last arugement of previous commands
# mkdir raj
# cd $_

ln – Hard Links and Softlinks
# ln /usr/bin/perl  /usr/local/bin/perl – To create a hard links from src to dest
# ls –I  – To Display the node number of files
# ln –s /usr/bin/perl  /usr/local/bin/perl – To Create a soft link

umask – default file and directory permission
# When you create a files and directories, the permission assigned to them depends on rge system’s default setting..
# unix has default 666 for regular files & 777 for directories
# umask –ENTER
# 022
This is an octal number which has to be subtracted from system default to obtain the actual default. This becomes 644 (666-022) for ordinary files and 755 ( 777 -022) for directories.
# User can set the umask such as umask 023.

touch – Changing the time stamp
# touch emp.lst – Create a file name called emp.lst
# touch 02161430 emp.lst – To Change the time stamp of file for MMDDhhmm format
# touch –a 02161430 emp.lst – To Change the access time stamp of file for MMDDhhmm format
# touch –m 02161430 emp.lst – To Change the modification time stamp of file for MMDDhhmm format

find – Locating files

Expression Used by find.

Example

Change File Permissions Recursively
# find . -type f -exec chmod 644 {} \;
# find . -type d -exec chmod 755 {} \;
# find . -name Configuration.php -exec chmod 666 {} \;

Find files modified in the last 48 hours, and in current folder and one level below
# find -maxdepth 2 -type f -mtime -2

To find all files modified in the last 24 hours (last full day) in a particular specific directory and its sub-directories:
# find /directory_path -mtime -1 –print

To find all files with regular file types only, and modified in the last 24 hours (last full day) in current directory and its sub-directories:
# find /directory_path -type f -mtime -1 –print
# find . -type f -mtime -1 –print

To find all files that are modified today only (since start of day only, i.e. 12 am), in current directory and its sub-directories:
# touch -t `date +%m%d0000` /tmp/$$
# find /tmefndr/oravl01 -type f -newer /tmp/$$
# rm /tmp/$$

To find all files in /home/user/demo directory
# find /home/user/demo -type f –print

To find all files in /home/user/demo directory with permission 777, enter:
# find /home/user/demo -type f -perm 777 –print

Apply new permission using the -exec option as follows:
# find /home/user/demo -type f -perm 777 -print -exec chmod 755 {} \;

To select directories and subdirectories use the following syntax:
# find /var/www/html -type d -perm 777 -print -exec chmod 755 {} \;

This first Linux find example searches through the root filesystem (“/”) for the file named “Chapter1”. If it finds the file, it prints the location to the screen.
# find / -name Chapter1 -type f –print

A nice thing to know is that on Linux systems and modern Unix system you no longer need the -print option at the end of the find command, so you can issue it like this:
# find / -name Chapter1 -type f

This next find command searches through the /usr and /home directories for the file named Chapter1:
# find /usr /home -name Chapter1 -type f

To search in the current directory, and all subdirectories, just use the . character to reference the current directory in your find commands, like this:
# find . -name Chapter1 -type f

This next command searches through the /usr directory for all files that begin with the letters Chapter, followed by anything else. The filename can end with any other combination of characters. It will match filenames such as Chapter, Chapter1, Chapter1.bad, Chapter-in-life, etc.:
# find /usr -name “Chapter*” -type f

This next command searches through the /usr/local directory for files that end with the extension .html. These file locations are then printed to the screen.
# find /usr/local -name “*.html” -type f

To find all directories named build under the current directory, use this command:
# find . -type d -name build

This command searches through the htdocs and cgi-bin directories for files that end with the extension .cgi. When these files are found, their permission is changed to mode 755 (rwxr-xr-x). This example shows that the find command can easily search through multiple sub-directories (htdocs, cgi-bin) at one time.
# find htdocs cgi-bin -name “*.cgi” -type f -exec chmod 755 {} \;

Find and display files last modified les than 90 days ago.
# find . -name “*” -mtime -3 -print

find everything in your home that has been modified more recently than “abc.txt”:
# find $HOME -newer ~joeuser/lastbatch.txt

For finding only files from all directories recursively
# find ./ -type f | wc -l

For finding only files from all directories recursively
# find ./ – type d | wc -l

How to Return a message when a file is not found using find command? OR
Find command return type OR
when the file is not found i want it to return some value OR
# find . -name raj.txt > raj.txt
# counter= `cat abc.txt | wc -l’
# if [$counter -gt 0]
# then
#                echo “File is found”
# else
#                echo “File is not found”
# fi
That’s nice, but what if I want to see the last modification time of these files, or their filesize? No problem, I just add the “ls -ld” command to my find command, like this:
find . -name “*.pl” -exec ls -ld {} \;

Count Total number of files in Directory and Subdirectory
# find . -type f | wc –l

Count Specific extention files in Directory and Subdirectory
# find . -type f -name \*.mnp |wc –l

Count only Directory
# find . -type d | wc –l

head – Displaying the beginning of a file
# head –n 3 filename
# vi `ls –t` | head –n 1` – Opens last modified file for editing

tail – Displaying the end of a file
# tail -3 filename
# tail –f filename             Monitering file live

Cut
# cut –c 6-12,24-32 filename – Cutting column
# cut –d \| -f 2,3 filename            – Cutting fields
# cut –d “|” –f 1,4- filename –To cut out the fields numbered 1,4,5 and 6.

Sort – Ordering a file
Sort Options

Examples:
# sort –t”|” –k 2 shortlist
# sort –t”|” –r –k 2 shortlist
# sort –t “|” –k 3,3 –k 2,2 shortlist
# sort –t”|” –k 5.7,5.8 shortlist
# sort numfile
# cut –d”|” –f3 filename | sort –u
# sort –m foo1 foo2 foo3

Uniq – Locate repeated and non-repeated lines
# sort dept.lst | uniq
# cut –d”|” –f3 emp.lst | sort | uniq –u                                 ( -u selects only lines which is not repeated)
# cut –d”|” –f3 emp.lst | sort | uniq –d                                 ( -d selects one copy of repeated lines)
# cut –d”|” –f3 emp.lst | sort | uniq –c

tr – Translating characters
# tr ‘|/’ ‘~-‘ < emp.lst | head –n 3             – To replace the | with a ~ and the / with a  -.
# head –n 3 emp.lst | tr ‘[a-z]’ ‘[A-Z]’     – Change first three lines from lower to upper.
# tr –d ‘|’ < emp.lst | head –n 3                                – To deleting characters

grep – Searching for a pattern
# grep “director” filename1 filename2
# grep “Rajesh Kumar” filename1
# grep –i ‘rajesh’ filename1                                         To Ignore case
# grep –v ‘rajesh’ filename1 > filename2                              To Select all except lines containing patterns
# grep –n ‘rajesh’ filename1                                       To Display line numbers
# grep –c ‘rajesh’ filename                                          Counting line containing pattern
# grep –l ‘rajesh’ *.lst                                                    -l options display only the name of files containing pattern
# grep –f pattern.lst emp.lst                                       Taking patterns from files

Grep a file, but show several surrounding lines?

For BSD or GNU grep you can use -B num to set how many lines before the match and -A num for th number of lines after the match.
grep -B 3 -A 2 foo README.txt

If you want the same amount of lines before and after you can use -C num.
grep -C 3 foo README.txt
This will show 3 lines before and 3 lines after.

Basic Regular Expression tables

Example:
# grep “[aA]g[ar][ar]wal filename
# grep “[aA]gg*[ar][ar]wal” filename
# grep “j.*Saxena” filename
# grep “^2” filename
# grep “7…$” filename
# grep “^[^2]” filename
# grep –E “[aA]gg?arwal” filename
# grep –E ‘sengupta|dasgupta’ filename
# grep –E ‘(sen|das)gupta’ filename

Editor
Awk  – http://www.thegeekstuff.com/2010/01/awk-introduction-tutorial-7-awk-print-examples/
Sed
vi

# sed – The Stream Editor
# sed ‘3q’ filename == head –n 3                              Quit after line number 3
# sed –n ‘1,2p’ filename                                                               Prints the first 2 lines. Must use –n with p
# sed –n ‘$p’ filename                                                   print last line
# sed –n ‘9,11p 7,9p $p’ filename
# sed –n ‘3,$ip’ filename                                              Don’t print line 3 to the end, display only line 1 and 2

# sed –n ‘/director/p’ filename                                 To print the lines which has pattern in filename
# sed –n ‘/dasgupta/,/saksena/p’ filename
# sed –n ‘1,/dasgupta/p’ filename
# sed –n ‘/[aA]gg*[ar][ar]wal/p’ filename
# sed –n ‘/sa[kx]s*ena/p /Gupta/p’ filename
# sed –n ‘/50…..$/p’ filename

# sed –n ‘director/w  dlsit’ filename
# sed –n ‘director/w dlist /manager/w mlist /executive/w elist’ filename
# sed –n ‘1,500w foo1 501,$w foo2’ filename

# sed ‘1i\
> #include <stdio.h>\
> #include<unistd.h>
>’ foo.c  >> $$                                                                    Include these include on beginning of the program
# sed ‘a\

‘ filename                                                                            # insert after every line this blank line
# sed “/director/d’ filename > filename2              -n option not to be used with d
== # grep –v “director” filename > filename2
# sed –n ‘/director/!p’ filename1 > filename2

# sed ‘s/|/:/’ filename | head -2
# sed ‘s/|/:/g’ filename | head -2
# sed ‘1,3s/|/:/g’ filename
# sed ‘1,5s/director/member /’ filename
# sed ‘s/^/2’ filename
# sed ‘s/$.00/’ filename

Sed tables

Vi – Editor                           

IMPORTANT – YOU SHOULD USE DOUBLE QUOTES ONLY WHEN PARAMETER EVALULATION OR command substitution is embedded within command

Write about command “w”

The post Linux Commands for User | Linux User Commands Reference appeared first on scmGalaxy.

iostat reports CPU, disk I/O, and NFS statistics.

mpstat reports processors statictics.
vmstat reports virtual memory statistics.

vxstat – This Utility can be used as well.

iostat reports CPU, disk I/O, and NFS statistics.

The iostat command generates two types of reports, the CPU Utilization report and the Device Utilization report. The first report generated by the iostat command is the CPU Utilization Report.

The report has the following format:

%user – Show the percentage of CPU utilization that occurred while executing at the user level (application).
%nice – provides statistics on a per physical device or partition basis.
Device – This column gives the device name
tps – Indicate the number of transfers per second that were issued to the device. A transfer is an I/O request to the device.
Blk_read/s – Indicate the amount of data read from the drive expressed in a number of blocks per second.
Blk_wrtn/s – Indicate the amount of data written to the drive expressed in a number of blocks per second.
Blk_read – The total number of blocks read.
Blk_wrtn – The total number of blocks written.
kB_read/s – Indicate the amount of data read from the drive expressed in kilobytes per second.
kB_wrtn/s – Indicate the amount of data written to the drive expressed in kilobytes per second.
wrqm/s – The number of write requests merged per second that were issued to the device.
r/s – The number of read requests that were issued to the device per second.
w/s – The number of write requests that were issued to the device per second.
rsec/s – The number of sectors read from the device per second.
wsec/s – The number of sectors written to the device per second.
await – The average time (in milliseconds) for I/O requests issued to the device to be served.
svctm – The average service time (in milliseconds) for I/O requests that were issued to the device.
%util – Percentage of CPU time during which I/O requests were issued to the device.

vmstat reports virtual memory statistics.

The report has the following format:

Procs – r: Total number of processes waiting to run
Procs – b: Total number of busy processes
Memory – swpd: Used virtual memory
Memory – free: Free virtual memory
Memory – buff: Memory used as buffers
Memory – cache: Memory used as cache.
Swap – si: Memory swapped from disk (for every second)
Swap – so: Memory swapped to disk (for every second)
IO – bi: Blocks in. i.e blocks received from device (for every second)
IO – bo: Blocks out. i.e blocks sent to the device (for every second)
System – in: Interrupts per second
System – cs: Context switches
CPU – us, sy, id, wa, st: CPU user time, system time, idle time, wait time

mpstat reports processors statictics.

reports processors statictics(mpstat – Report processors related statistics and mpstat displays CPU statistics )

mpstat :- mpstat displays CPU statistics
mpstat -A :- Display all information
mpstat -P ALL :- Display CPU statistics of individual CPU (or) Core

Reference:
http://www.linux-tutorial.info/modules.php?name=ManPage&sec=1&manpage=iostat
http://www.thegeekstuff.com/2011/07/iostat-vmstat-mpstat-examples/

The post Linux Performance Monitoring using iostat, mpstat and vmstat | Linux Performance Monitoring Guide appeared first on scmGalaxy.

Main Responsibilities of the Linux System Administrator is as follows:

1. Maintaining User Accounts
2. Security
3. Managing the disk space and Backup
4. Provisiom the new Linux Server based on the need
5. Linux Server Updates and Patching
6. Authentication and Authorization Management
7. Trubleshooting of Linux Severs and QA Deployments
8. Managing the Large number of VMS in VMWARE
9. Montoring all the vms and their health
10. Montoring Major Important Services
11. Backup & Restore all the imporant data of the servers
12. Server and OS process monitoring
13. Disk managment and montoring

The Administrator’s Privileges:

1. Change the contents or attributes of any file like its permission and ownership
2. He can delete any file eith rm even if it is write-protected.
3. Initiate or Kill Any Process
4. Change any user’s password without knowing the existing one
5. Set the system clock with date
6. Limit the maximum size of files that users are permitted to create with ulimlit
7. Controls users access to the scheduling services like at and cron
8. Control users access to many networking services like Telnet, FTP, etc

The post Main Responsibilities of the Linux System Administrator | What Linux System Administrators do ? appeared first on scmGalaxy.

To find a program not on this list (and there are hundreds), try the man program with the -k option followed by a keyword, for example,
man -k tape
to find all on-line manual entries that refer to programs that work with tapes.

Terminal control characters for C-shell (csh)

Also see a list of special characters that should not be used in filenames.

Login and authentication

Information

File management

Display contents of files

Directories

Disks

Special character handling for C-shell (See man csh)

Controlling program execution for C-shell (See man csh)

Controlling program input/output for C-shell (See man csh)

Email and communication

Editors and formatting utilities

X Window client programs (output to X terminal or server)

TeX typesetting system

Printing (BSD based)

Interpreted languages and data manipulation utilities

Graphics and mapping

Networking/communications

Compilers, interpreters and programming tools

Programming libraries (see man library_name)

Tape manipulation and archiving

The post Common unix commands and utilities | unix commands and utilities Guide appeared first on scmGalaxy.

To install svn in linux and make it fully working , I found it really tough and it has taken my lots of time. I am thankful to Sanjay, who helped me in this and without him it won’t be possible.While installing this you will miss a small thing and you got stuck.But this is not at all tough like open source it’s really very easy.

Why I have choosed this topic to write is that, those who are using it first time will need some time to get full of subversion.

Now the latest version of svn is 1.6.9.

To install svn first you need svn tar file. Which can be downloaded easily from here or you can run these commands (depending on your required version).

wget http://subversion.tigris.org/downloads/subversion-1.6.9.tar.gz

wget http://subversion.tigris.org/downloads/subversion_deps-1.6.9.tar.gz (It contains the library required by svn)

This you can download any where, Here I am creating a folder svn inside /usr/local directory.(/usr/local/softwares/svn/).(So it will be easy for me to specify paths and you to understand).

To start the installation process first untar this two file.

tar -xvzf subversion-1.6.9.tar.gz

tar -xvzf subversion_deps-1.6.9.tar.gz (After untar you won’t find any particular folder named subversion_deps-1.6.9. Don’t worry for that it is keeping all the libraries files inside subversion-1.6.9)

Now have to configure it, but before that we have to check whether our system is having all the dependies or not, like APR(Apache Portable Runtime) and APR utility.

If it’s not there then we can get it from here,

apr-1.2.12.tar.gz

apr-util-1.2.12.tar.gz

once downloaded you can start configuring it.

tar -xvzf apr-1.2.12.tar.gz

cd apr-1.2.12

./buildconf

./configure

make

The apr util directory requires apr directory, so we need to specify path for that.

tar -xvzf apr-util-1.2.12.tar.gz

cd apr-util-1.2.12

./buildconf –with-apr=/path to apr directory (/usr/local/sofwares/svn/apr-1.2.12)

./configure –with-apr=/path to apr directory (/usr/local/sofwares/svn/apr-1.2.12)

make

The other directories we have to check before installation are,

autoconf 2.50 or newer (autoconf –version)

libtool 1.4 or newer (this you can find inside subversion-1.6.9 folder)

Neon Library 0.25.x or 0.26.x (inside subversion-1.6.9 folder)

Berkely DataBase (If it’s not there you have to install it.)

Download the file, db-4.6.21.tar.gz .

Apache web server greater then 2.0.49 (httpd -version)

zlib (inside subversion-1.6.9 folder)

After checking all this, we can start installation process,

cd subversion-1.6.9

./autogen.sh

./configure –with-berkelay-db=/usr/local/softwares/svn/db-4.6.21 (path of berkelay data base)

make

make install

Once we have finished that we need to map svn with apache.

Before that we have to check whether mod_dav_svn and mod_authz_svn modules are present or not,if not then install it.

yum install mod_dav_svn

and add this in /etc/httpd/conf/httpd.conf file

LoadModule dav_svn_module modules/mod_dav_svn.so

LoadModule authz_svn_module modules/mod_authz_svn.so

Make sure you will add these lines after LoadModule dav_module modules/mod_dav.so.

Now create one repository with svnadmin command.Run this command inside your subversion folder.

svnadmin create repos

after that you can check with,

ls repos

conf dav db format hooks locks README.txt

This full path you have to specify in SVNPath.

Then at the end of the httpd.conf file you have to add

#for svn path

DAV svn

SVNPath /usr/local/softwares/svn/subversion-1.6.9/repos

now restart ur apache.

For security purpose to give authentication to the user we have to create authentication file with the command,

htpasswd -cm /etc/svn-auth-file user_name (test)

New password : test123

Re-Type passwd : test123

And to specify which access you want to give the user, create svn-access-file inside /etc.

Inside this file add code as,

[/]

* = rw

This will give authentication to every user specified in Require user inside location.

You can specify this inside httpd.conf file as,

DAV svn

SVNPath /usr/local/softwares/svn/subversion-1.6.9/repos

AuthzSVNAccessFile /etc/svn-access-file

AuthType Basic

AuthName “Subversion repository”

AuthUserFile /etc/svn-auth-file

Require user user_name

Now you are ready to import files in the repository, with the following command.

svn import -m “Initial import.” path(from where you want to import file) file:///usr/local/softwares/svn/subversion-1.6.9/repos/(repository path)

after running this command don’t worry it is not goin to display any thing inside repos folder. To check that you can run it in the browser.

http://localhost(you have to give your domain name)/svn/repos

Now you are ready to checkout the files with any svn client. For linux user smartsvn is best.

After doin this you can start ur smartsvn client and can follow these steps,

check out project from repository -> manage -> add -> enter svn url

enter ur url here http://localhost/svn/repos

enter ->ok

server name and repository path it will take automatically. click next, choose user radio button and give user name and password.

follow the steps to fetch the files.

To install smartsvn, first get the smartsvn tar file.

untar the file, with the command

tar -xvzf smartsvn-version.gz

for smartsvn first check the correct version of java is available or not, with

java -version command.If it is coming like this then you can proceed.

java version “1.5.0_14?

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_14-b03)

Java HotSpot(TM) Server VM (build 1.5.0_14-b03, mixed mode)

Sometimes java will be installed but not the JRE. In that case simply re-install java.

Can install the latest version of java with rpm bin file.

jdk-1_5_0_14-linux-i586-rpm.bin

./jdk-1_5_0_14-linux-i586-rpm.bin

go through the license and say yes.

It will installed in /usr/java/

Now have to make chnages in .bash_profile file.

cd /root

vi .bash_profile

give JAVA_HOME path.

JAVA_HOME = /usr/java/jdk1.5.0_14

Then compile it with the command,

source .bash_profile

then again check with java version.

Now you are ready to utilise the full feature of subversion

The post How to install subversion on Linux? appeared first on scmGalaxy.

Grep scans its input for a pattern, and can display the selected pattern, the line numbers of the filenames where the pattern occurs, The command uses the following syntax

grep options pattern filesname(s)

grep searches for pattern in one or more filenames.

Example for Grep command:

1. grep “sales” emp.lst
2. grep “director” emp1.lst emp2.lst
3. grep ‘jai sharma’ emp.lst
4. grep “jai Sharma $var” emp.lst

—————-Grep options—————————

Ignoring Case (i) When you look for a name, but you are not sure of the case, grep offers the –i (ignore) option which ignores case for patteen matching.

> Grep –i ‘agarwal’ emp.lst

Deleting Lines  or Inverse(-v): -v (inverse) option selects all except lines containing the pattern. Thus, you can create a file other list containing all but director.

> Grep –v “director” emp.lst > other list

Displaying line Numbers (-n): The –n(number) options displays the line numbers containing the pattern, along with the lines:

> grep –n ‘marketing’ emp.lst

Counting Line Containing patterns (-c): The –c (count) option counts the number of lines containing the pattern ( which is not the same as number of occurrences).

1. grep –c director emp.lst
2. grep –c director emp*.lst

Displaying Filenames (-l): The –l (list) option displays only the files names of files containing the pattern.

> grep –l ‘manager’ *.lst

Matching Multiple Patterns(-e): With the –e option, you can match the three agarwals by using grep like this:

> grep –e “Agarwal” –e “aggarwal” –e “agarwal” emp.lst

Taking patterns from a file (-f): we can place all patterns in a separate file, one pattern per lin. Grep takes inputs from there with the –f option:

> grep –f pattern.lst emp.lst

The post Unix Command: Grep – Quick Reference – Pattern – Examples – Options appeared first on scmGalaxy.

Set properties HOMEDIR in build.xml which will be set through user logged in the current system..

Example:

<project name=”test” default=”myhome”>

    <property environment=”env”/>

    <target name=”myhome”>

        <echo message=”My home is ${env.HOME}”/>

    </target>

</project>

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Basic of Unix Presentation

The post Basic of Unix – Presentation | Unix Learning Reference – Guide appeared first on scmGalaxy.