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How to define multiple environment variables in a shell script?


 
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# 1  
Old 04-16-2020
How to define multiple environment variables in a shell script?

Hi All,
I am running a shell script on centos 7 to get some variable values and want to declare them as environment variables so that i will use them in another shell script.

I am using below script i am able to define one environment variable but it's not allowing me to do for another variable.

Can someone please help me on this issue.

Code:
 path=$(find $config_path -name abc.txt 2>/dev/null )

domain_path=$(cat $path |grep "domain location" )
 
boot=$(find $config_path -name boot.properties 2>/dev/null |head -1 )

 user_name=$(cat $boot |grep username)
echo 'export NAME=$user_name' >> ~/.profile

  passwd=$(cat $boot |grep password)
  echo $passwd
  echo 'export TEST=$passwd' >> ~/.bash_profile

# 2  
Old 04-16-2020
Quote:
Originally Posted by sravani25
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.
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Can someone please help me on this issue.
.
.
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What exactly is the issue? As always: pls describe the error meticulously, add error messages and misbehaviour.


What I can say from looking at your script is that shell variables are not expanded within single quotes, so neither $user_name nor $passwd values will be passed to the .*profile files. If that is by intention, make sure the vaiables are defined in those scripts.
# 3  
Old 04-16-2020
You alter both ~/.profile and ~/.bash_profile.

~/.bash_profile is for a bash login shell.
At login ~/.profile is for all sh-style shells (sh,ash,dash,jsh,psh,ksh,bash,...), but bash runs ~/.bash_profile instead if present.
Some graphical desktops provide a login but do not run a login shell, then bash runs ~/.bashrc.
Some Linux distros might run ~/.bash_profile (or ~/.profile) from /etc/bash.bashrc that is run prior to ~/.bashrc.

Yes, it's a mess.
# 4  
Old 04-17-2020
Hi Rudi,

I am trying to set multiple environment variables using shell script.

I tried below commands to set the environment variables in the shell script(as example i shared one variable info):
Code:
abc=$(find $config_path -name xyz.xml 2>/dev/null)
user_name=$(cat $abc |grep username )
export NAME=$user_name

when i executed the shell script it's executed successfully but when i am trying to print the environment variable it's returning empty value
echo $NAME -- is giving empty value.

Can you please let me know what i need to change to set the environment variable ?.

Moderator's Comments:
Mod Comment please wrap your samples/codes in CODE TAGS as per forums rules.

Last edited by RavinderSingh13; 04-17-2020 at 12:22 AM..
# 5  
Old 04-17-2020
EXPORT allows shell variables to be passed onto sub processes of the current shell not back up to the calling process.

If you want a child script to set environment variables in the parent (calling) script source the child script. Example:
Code:
$ NAME=
$ cat sc_1
abc="Test abc"
def=${abc% *}
export NAME=$def
$ ./sc_1
$ echo $NAME

$ . ./sc_1
$ echo $NAME
Test

See how the second instance sc_1 is sourced into the current shell by using . ./sc_1 (or source ./sc_1 if you prefer the clearer long-hand form). Any variables set will now be in the current shell. Think of this as reading the commands in the child script into the current process not spawning a new shell to run sc_1 which loses any environment vars after it finishes.
This User Gave Thanks to Chubler_XL For This Post:
# 6  
Old 04-17-2020
Quote:
Originally Posted by sravani25
.
.
.
Code:
abc=$(find $config_path -name xyz.xml 2>/dev/null)
 user_name=$(cat $abc |grep username )
export NAME=$user_name

when i executed the shell script it's executed successfully but when i am trying to print the environment variable it's returning empty value
echo $NAME -- is giving empty value.

$NAME being empty is a strong indicator that $user_name is empty and the "command substitution" fails / results in an empty string. I guess its because the file called $abc doesn't exist. and the cat cats nothing.



Quote:
Can you please let me know what i need to change to set the environment variable ?
It would help if people knew the entire scenario. Variables in which environment do you want to set? Your current session? Future sessions? Why the echoing into the varying .profiles?
# 7  
Old 04-17-2020
You're using find to search directories, nice.
But then you're using the variable without checking if it's has one , none or more results.

Further, I assume that you want the variable $user_name to actualy contain (just) the "<username>", and not the string "username + <username>".
This said, you might want to take care of that, afterwhich you might want to use something like this:
Code:
if [[ -n "$user_name" ]]
then    export NAME=$user_name
else    echo "<user_name> is empty"
        # If it is within a script:
        #exit 1
fi

As the string might become empty after removing the found string pattern from it's content ("username + <username>"), if it even finds anything - as in your current case.
This said, you might want to make sure where your find starts from.

I would also suggest to take care of multiple finds (tempfiles) within a a for loop.
This is my suggested handling for all dynamic (find, locate, *, ls, which, etc) variables.

Hope this helps

Last edited by sea; 04-17-2020 at 05:18 PM..

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