[clue] env variables

Mon Jun 24 17:03:03 MDT 2013

Just a note that removing the #! statement at the top of the file is
usually a bad idea. That doesn't directly start a new shell, that tells the
system (not sure if it's bash itself, or if it's a kernel thing) which
interpreter to use for the script. You can get weird results if you leave
that out and make the script executable.

It does though create a new subshell as was mentioned, which always happens
with script execution (having nothing to do with #!), which is why those
env_vars don't show up in the parent shell. In order to get them to show up
in the parent shell, you have to source them from the parent shell:

04:57 PM:qhartman at qhstation$ cat foo.sh
#!/bin/bash
export FOO=bar

CWD:~
04:57 PM:qhartman at qhstation$ ./foo.sh

CWD:~
04:57 PM:qhartman at qhstation$ echo $FOO

CWD:~
04:57 PM:qhartman at qhstation$ source foo.sh

CWD:~
04:58 PM:qhartman at qhstation$ echo $FOO
bar

If you need to have those vars set outside of the context of the script you
are running, you need to add or modify those vars in the appropriate user's
login shell config (usually .bashrc), and then the next time that user
invokes a shell they will be set how you want.

On Mon, Jun 24, 2013 at 3:28 PM, Mark G. Harvey <markgharvey at yahoo.com>wrote:

>
>
> so removing #!/bin/bash/ at the top of the script to stay within the same
> shell session doesn't make any detectable difference
>
> I also added sourcing the file where the variables are set ( # source /etc/profile.d/00_jdk.sh
>  )
>
> the variables PATH and JAVA_HOME show up correct when the script is
> running ... but when finished, the variables are still not changed
>
> [root at 87148-mondev01 ~]# echo $PATH
> /usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
>  ... should be appended with /usr/java/jdk1.7.0_21/bin
> [root at 87148-mondev01 ~]# echo $JAVA_HOME
> ... should have an entry /usr/java/jdk1.7.0_21/bin ... but it is blank
>
>
>
>
>   ------------------------------
>  *From:* "dennisjperkins at comcast.net" <dennisjperkins at comcast.net>
> *To:* CLUE's mailing list <clue at cluedenver.org>
> *Sent:* Monday, June 24, 2013 2:56 PM
>
> *Subject:* Re: [clue] env variables
>
> The proper place for these might be in one of the Bash config files.
>
> ------------------------------
> *From: *"Stephen Queen" <svqueen at gmail.com>
> *To: *"Mark G. Harvey" <markgharvey at yahoo.com>, "CLUE's mailing list" <
> clue at cluedenver.org>
> *Sent: *Monday, June 24, 2013 2:37:49 PM
> *Subject: *Re: [clue] env variables
>
> When you add
> #!/bin/bash
> to the top of your script, you are starting a new shell. When the script
> completes, it exits that shell. Instead "source" you environmental
> variables. Create a file my_env that contains your export commands
> # cat my_env
> export JAVA_HOME=/usr/java/jdk1.7.0_21
> export PATH=$PATH:/usr/java/jdk1.7.0_21/bin
>
> Then source the file
> . my_env
> (space between . and my_env, does not need to be executable).
> Now when you
> # echo $JAVA_HOME
> usr/java/jdk1.7.0_21
> #
>
> Steve
>
>
>
>
> On Mon, Jun 24, 2013 at 1:54 PM, Mark G. Harvey <markgharvey at yahoo.com>wrote:
>
> CLUE experts,
>
> This puzzle is likely simple for you folks, but it has me stumped.  I've
> done considerable digging but have found mixed advice.
>
> I've created a script to download from a local repo via wget an rpm to
> install JDK ... no problem there.
>
> Here's the part I can't get right ... setting the variables so I can run
> scripts to install Tomcat ... Any attempt will bomb if it can't find
> /usr/java/jdk1.7.0_21/bin
>
>
> # set JAVA_HOME variable   ... tried in vain
> echo "setting JAVA_HOME variable variable for the session"
> JAVA_HOME=/usr/java/jdk1.7.0_21
> # export JAVA_HOME variable  ... tried in vain
> echo "exporting JAVA_HOME variable variable for the session"
> export JAVA_HOME=/usr/java/jdk1.7.0_21
> echo "JAVA_HOME variable: $JAVA_HOME"
>
> # set PATH variable for the session   ... tried in vain
> echo "setting PATH variable for the session"
> PATH=$PATH:/usr/java/jdk1.7.0_21/bin
> # export PATH variable for the session
> echo "exporting PATH variable for the subsequent sessions & processes"
> export PATH=$PATH:/usr/java/jdk1.7.0_21/bin
> echo "show PATH variable: $PATH"
>
> sleep 3  # wait
>
> # create script to set JAVA_HOME & PATH variables in
> /etc/profile.d/00_jdk.sh script for all accounts
> # use echo command with single quotes to write the literal statement to
> the script
> touch /etc/profile.d/00_jdk.sh
> echo '#!/bin/bash' >> /etc/profile.d/00_jdk.sh
> echo '# set JAVA_HOME in /etc/profile.d/00_jdk.sh script for all accounts'
> >> /etc/profile.d/00_jdk.sh
> echo 'JAVA_HOME=/usr/java/jdk1.7.0_21' >> /etc/profile.d/00_jdk.sh
> echo '# set PATH in /etc/profile.d/00_jdk.sh script for all accounts' >>
> /etc/profile.d/00_jdk.sh
> echo 'PATH=$PATH:/usr/java/jdk1.7.0_21/bin' >> /etc/profile.d/00_jdk.sh
>
> sleep 3  # wait
>
> echo "review contents of /etc/profile.d/00_jdk.sh"
> cat /etc/profile.d/00_jdk.sh
>
>
> ... results of install ... added some blank lines for readability ...
>
> [root at 87148-mondev01 ~]# ./DEV_install_jdk1.7-1.0.0.sh<http://dev_install_jdk1.7-1.0.0.sh/>
>
> installation:  Oracle/Sun jdk 1.7 64-bit
> remount /tmp with execute privledge
> changed to /tmp
> Pulling package from Artifactory Repo Management Server
> --2013-06-24 13:24:38--
> https://<RepoHost>/artifactory/simple/ext-release-local/oracle/jdk/7u21-linux/jdk-7u21-linux-x64.rpm
> Resolving <RepoHost>... 10.33.44.10
> Connecting to <RepoHost>|10.33.44.10|:443... connected.
>
> HTTP request sent, awaiting response... 200 OK
>
> Length: 85388149 (81M) [application/x-rpm]
> Saving to: “jdk-7u21-linux-x64.rpm”
>
> 100%[=======================================================================================================================================>]
> 85,388,149  52.7M/s   in 1.5s
>
> 2013-06-24 13:24:40 (52.7 MB/s) - “jdk-7u21-linux-x64.rpm” saved
> [85388149/85388149]
>
> jdk downloaded
> check /tmp/ contents for jdk
> -rw-r--r--. 1 root root 85388149 Jun  6 16:46 jdk-7u21-linux-x64.rpm
> install jdk rpm
> Preparing...                ###########################################
> [100%]
> package jdk-2000:1.7.0_21-fcs.x86_64 is already installed      ........
> due to subsequent running of this script
> install jdk complete
>
> setting JAVA_HOME variable variable for the session
> exporting JAVA_HOME variable variable for the session
>
> ... when tested in the script, the correct answer shows up ...
>
> JAVA_HOME variable: /usr/java/jdk1.7.0_21
>
> setting PATH variable for the session
> exporting PATH variable for the subsequent sessions & processes
>
> ... when tested in the script, the correct answer shows up ...
>
>
> show PATH variable:
> /usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin:/usr/java/jdk1.7.0_21/bin:/usr/java/jdk1.7.0_21/bin
>
> review contents of /etc/profile.d/00_jdk.sh
> #!/bin/bash
> # set JAVA_HOME in /etc/profile.d/00_jdk.sh script for all accounts
> JAVA_HOME=/usr/java/jdk1.7.0_21
> # set PATH in /etc/profile.d/00_jdk.sh  script for all accounts
> PATH=$PATH:/usr/java/jdk1.7.0_21/bin
> remount /tmp removing execute privledge
> finished
>
>
> ... after script runs, when tested from CLI, variables not not correct ...
>
> [root at 87148-mondev01 ~]# echo $JAVA_HOME
>
> [root at 87148-mondev01 ~]# echo $PATH
> /usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
>
>
>
> [root at 87148-mondev01 ~]# exit
> logout
>
> [vwadmin at 87148-mondev01 ~]$ su -
> Password:
>
>
> ... now the variable additions show up ... they come from
> the /etc/profile.d/00_jdk.sh script created as part of the JDK download &
> install ...
>
> [root at 87148-mondev01 ~]# echo $PATH
>
> /usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/java/jdk1.7.0_21/bin:/root/bin
>
> [root at 87148-mondev01 ~]# echo $JAVA_HOME
> /usr/java/jdk1.7.0_21
>
>
>
> ... How can I get the variables to be available for the current root
> session & usable for subsequent installations?  Trying to avoid the logout
> / login ...
>
>
>
> Thanks for your help.
>
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