Bash Scripting-2- Using VARIABLES in Linux shell scripts

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Bash Scripting-2- Using VARIABLES in Linux shell
scripts
Posted by Prince DAN January 13, 2020 in DevOps
In this tutorial, we will learn more about using
variables in Linux will also create some simple
bash scripts utilizing global environment
variables local variables. As mentioned in our
earlier tutorial, we can create a local variable
the following way, new_variabletest-value
Example schoolTHE LINUX GURUS Recommended
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Using local Variables in Linux
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• Now lets create a simple script utilizing this
  and another local variable,
• !/bin/bash NAMEPrince DAN
• SCHOOLTHE LINUX GURUS
• echo NAME echo SCHOOL
• echo My name is NAME i am a teacher at
  SCHOOL
• Save the script close the editor. Now before we
  execute this script, please read the following
  points,
• 1/bin/bash is called as shebang it tells the
  interpreter that following lines are written to
  be executed in bash,
• To call or to use variables in the script, we use
  followed by the name of variables,
• lastly we need to provide the execute permissions
  to the script to run it. Use the following
  command to provide the rights,
• chmod x simple_script.sh
• Now that we have to execute the script, the
  output will be,

Using global variables in scripts
So we already have some environment variables
setup by default on all the Linux machines. Some
of these variables are, UID, USER, HOME (you can
get complete list with the set command). Now
lets utilized these variables, vi
simple_script_2.sh
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Create the following script, !/bin/bash echo
Current user is USER echo USER has UID
UID echo his home path is HOME Save the
file execute the script, output will be,
./Simple_script_2.sh Current user is test-user
test-user has 453 UID his home is
/home/test-user Notice that we have not declared
the values for mentioned variables in our script
values are being captured from the environment
variables.
Using command substitution in variables
Command substitution is another way we can
utilize variables, so with command substitution
we will assign the output of a command as the
value for a variable, new_date(date ymd)
echo new_date The same can be utilized in the
scripts as well. This is all for now on using
variables in Linux.We will discuss more about
bash scripting in our coming tutorials, please
feel free to share the tutorial or send in any
questions or queries using the comment box below.
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