Process ID Allocation in Linux.

In `/proc/sys/kernel/pid_max`. Max PID value will define. Example PID 17 issued just now, then PID 18 will be next. By the time of issuing PID 18 even though PID 17 wasnt alive still kernel will issue PID 18 and this will create a unique PID issue behaviour and till what value process IDs can be issues will be define at /proc/sys/kernel/pid_max

so till that value process IDs will be issues and then it will start from the beginning.

“`bash
[root@967dd7743677 /]# cat /proc/sys/kernel/pid_max
99999
[root@967dd7743677 /]#
“`

bash lock user in 10 min

“`
$ echo usermod –lock ftp_cidtest01raja37 | at now + 1 minutes

“`

$ adduser someuser
$ echo usermod –lock someuser | at now + 10 minutes

CentOS 7 for 32-bit released

Hello Team,

I came to know very late that CentOS 7 released for 32 bit PC’s.

Few packages still  not available but I like centOS very much than other OS.

Download here CentOS 7

chage : Linux Command

chage is a Linux command. chage is used to change user password expiry information.

1. To set every user must reset his password on his first login use command as

sudo chage -d0

2. To see when a user reset his password and when his password expires etc we can use below command

sudo chage -l

3.To set or modify last password reset date of a user this command

sudo chage -d 2010-09-10 testing

4.To set password expiry for a user , use this command

sudo chage -E 2015-10-10 testing

For more information , Please visit manpage :chage

awk : Linux command

=> How to turn column into row with each filed separated by comma

awk -vORS=, '{ print $2 }' file.txt | sed 's/,$/\n/'

and you can also use

echo "data" | awk -vORS=, '{ print $2 }' | sed 's/,$/\n/'

Thank you.

Regards

Raja

netstat : Linux Command

1. Command to see which port is using by what service

sudo netstat -peant | grep ":8000 "

diff : Linux Command

1. To compare two directories contents

diff -r dir1/ dir2

grep : Linux Command

1. To search two strings at a time

grep ‘string1\|string2’ filename.txt

How to set password with vim

Setting password with vim editor is pretty simple .Open your terminal and type as

vim +X filename.txt

After it got opened it will ask for password, Enter same password two times and thats it. your file got protected by password. next you want to open it then you must now the password

…..

Record Terminal session as text

I have gone through some wonderful command today named as script. You know what it do , it will simply record all your terminal sessions as text.

Usage : script <filename>

Example:

In the example you can see, after I typed as script terminal01 , its started storing all the text I am typing after it and its stopped doing that after I have typed exit.

I have seen the same what I have typed in the terminal with more terminal01 command. you can see it in the image.

Hope that helps.