Variable types:
---------------
1. Local variables / user defined variables.
variables created by user

2. system / predefined variables.
variables created by system
env ==> command to check system defined variables

 

script3: write a script to create a variable (sportsman=viratkohli) & verify the variable creation using echo command:
----------------------------------------------------------------------------------------------------------------------
[ec2-user@ip-172-31-6-171 ~]$ cat vars_check.sh
#!/bin/bash
sportsman=viratkohli
echo "my fav sportsamen is $sportsman"

script4: write a script to have employee data coming as variables & verify the variable creation using echo command:
----------------------------------------------------------------------------------------------------------------------
[ec2-user@ip-172-31-93-35 ~]$ cat employee_data.sh

#!/bin/bash
EMP_NAME=alice
EMP_ID=54234
EMP_LOC=bangalore
EMP_STATE=karnataka
echo "Display employee name $EMP_NAME "
echo "Display emloyee id $EMP_ID "
echo "Display employee location $EMP_LOC "
echo "Display employee state $EMP_STATE "

 

script5: script to check harware resources:
-------------------------------------------
[ec2-user@ip-172-31-6-171 ~]$ cat ram_usage_check.sh

#!/bin/bash
echo "Current free ram available is..."

free -m | grep Mem | awk -F " " '{print $4}'
#free -m

echo "current disk usage is..."
df -kh .

echo "number of cpu...."
nproc

 

 

Grep
----
grep is used to search the pattern (keyword) in a file.
if pattern is found, it will print all matched lines /entire line

syntax: grep <pattern_to_search> fileName

Note: Pattern = name =string all are same

---------------------------------------------------
SI City_Name Population State
1 bengaluru 1.4 crore karnataka
2 mumbai 2.5 crore maharashtra
3 newdelhi 1 crore delhi
4 chennai 90 lakhs tn
5 kolkata 1.2 crore westbengal
6 ahmedabad 60 lakhs gujarat
7 hyderabad 70 lakhs andhrapradesh
8 pune 45 lakhs maharashtra
9 Hubli_dharwad 10 lakhs karnataka
10 gurgaon 10 lakhs haryana
---------------------------------------------------