What is the importance of Parameter $?
Parameter $? stores the exit status of the last command
When I can use the parameter $?
parameter $? can be used in scenarios where we want to execute some commands based on the status of the last command
The other scenario is if we want to display the status of the last executed command
How I can increase the size of the history command
$HISTSIZE is the built in variable which can be altered to increase/decrease the size of the history command
What are the operators used as logical and conditional execution in bash Shell programing
$$ is used as Logical and operator
|| is used as Logical or operator
How to identify the process id of last background job
$! can be used
How to use the command line arguments in shell programming
if we execute the shell programming as
shell_name arg1 arg2 arg3 arg4
for_instance
run_program 12 13 14 15
Here
$0 is run_program, which is the program name
$1 is 12
$2 is 13
$3 is 14
$4 is 15
$# is 4 which is total number of command line arguments
