Run source in bash execution - bash

Quick run down of what I'm doing, I'm making python development environments on my computer using virtualenv. I'm not one to remember all these commands, so I like to build simple(noob-ish) script that will help me.
Problem
As you see on step 2 in the Basic Usage section of the documentation. I need to run a command:
$ source venv/bin/activate
This activates my python environment. So I've tried a mixture of functions and eval. As mentioned, I am a bit of a noob when it comes to bash scripts.
My Code
File: fpyenv
#!/bin/bash
# $ cd ~/scripts/
# $ chmod u+x <filename>.sh
activateSrc(){
eval '$(source "${1}"/bin/activate)'
}
if [[ $1 == '' ]];
then
printf "ERROR: Missing Filename\n"
else
printf "Creating Virtual Environment $1\n"
# This creates the environment
virtualenv $1
printf "Do you want to activate $1 as your virtual environment?(y/n)\n"
# Get answer from user
read answer
if [[ $answer != 'y' ]];
# Said No
then
printf "Did not set $1 as your virtual environment\n"
else
# Said Yes
activateSrc $1
printf "Set $1 as your virtual environment\n"
fi
fi
This is what it should look like:
Step 1
myComputer $ fpyenv venv
returns
Creating Virtual Environment venv
Do you want to activate venv as your virtual environment?(y/n)
Step 2(user inputs y/n)
y
returns
Set venv as your virtual environment
(venv)myComputer $
But what I'm getting is:
Set venv as your virtual environment
myComputer $
So it doesn't run the source venv/bin/activate. Does anyone know what I'm doing wrong? I've looked through many answers, but given that source is commonly used in a different way in bash scripts, the answers I'm getting are no help. Thank you in advance!
FIX:
Change activateSrc to:
activateSrc(){
source $1/bin/activate
}
And execute script like this:
myComputer $ . fpyenv venv

It runs source just as written. The thing is that you need to source this new script as well, otherwise it just runs in a subshell and any changes made by the sourced script are lost when the subshell exits.

Related

Unable to run an interactive shell script using conda run

I have this script "/home/prod/test.sh"
#!/bin/bash
echo Hello, who am I talking to?
read varname
echo It\'s nice to meet you $varname
I was expecting that when I run this command
conda run -n myenv /home/prod/test.sh
I will see a prompt waiting for me to enter the value for varname , instead I got
(base) prod#dev-box:~$ conda run -n reportz /home/prod/test.sh
Hello, who am I talking to?
It's nice to meet you
(base) prod#dev-box:~$
Would very much appreciate a response detailing, how I can use conda to run an inetractive shell script ?
[Edit]
Replaced read varname with read -r varname < /dev/tty
It did wait for my input, but without displaying the output resulting from the echo statement echo Hello, who am I talking to?
Solution I'm looking for - the script should run with conda run command exactly as it would in a typical shell env.
The conda run command defaults to buffering I/O. To have interaction, one needs to include the --no-capture-output flag.
conda run -n myenv --no-capture-output /home/prod/test.sh
This feature was introduced in Conda v4.9.0 (Change Log).

using environment variables in service script

I am facing an issue using environment variables in my service script.
In my services script, i am using an environmental variable i.e. INSTALL_DIR whose value may vary on different system. I have to get the installation directory from $INSTALL_DIR and then i have to start the service. when i am running the service script the environment variable is not sourced at all.
Is it possible to source the installation directory from INSTALL_DIR environment variable. another option i can think is dynamically creating the service script using INSTALL_DIR environment variable.
echo "INSTALL DIR: ${INSTALL_DIR}"
name=`basename $0`
pid_file="/var/run/$name.pid"
get_pid() {
cat "$pid_file"
}
is_running() {
[ -f "$pid_file" ] && ps `get_pid` > /dev/null 2>&1
}
Start()
{
echo "Starting Application"
if is_running; then
echo "[`get_pid`] Already Started"
else
if [ -z "$user" ]; then
nohup $INSTALL_DIR/bin/application 2>&1 &
else
nohup sudo -u "$user" $cmd 1> $INSTALL_DIR/bin/application 2>&1 &
fi
echo $! > "$pid_file"
if ! is_running; then
echo "Unable to start, see logs"
exit 1
fi
echo "[`get_pid`] Started"
fi
}
I am trying to run the application using following command
service application start
In my services script ... I have to get the installation directory from $INSTALL_DIR and then i have to start the service.
Your question isn't really about shell scripting, but about your system's startup. Unfortunately that process varies by Linux distribution, and tends to be poorly documented.
For example, man service says, service runs a System V init script or upstart job in as predictable an environment as possible, removing most environment variables and with the current working directory set to /., but man upstart says:
$ man -k upstart
upstart: nothing appropriate.
Not only that, but the service manpage specifically lists the environment variables a script will start with. Needless to say, yours isn't among them.
The traditional approach to parameterizing startup scripts is to put the information in a known file, normally in /etc, and reference that file in the script. In your case, you could do something like:
INSTALL_DIR=$(cat /etc/my-install-dir.cfg)
and then proceed accordingly.
There might be ways to coerce your startup to support other environment variables. But, sooner or later, the information you need has to be stored somewhere on the filesystem. It seems to me the simplest approach is to reserve a filename to hold that information, and read that file directly.
Use this below code in your script.
if [[ -z "${INSTALL_DIR}" ]]; then
echo "INSTALL_DIR is undefined"
else
INSTALL_DIR=<<your installation directory>>
fi

Simple Bash Script Error and Advice - Saving Environment Variables in Linux

I am working on a project that is hosted in Heroku. The app is hard coded to use Amazon S3 and looks for the keys in environment variables. This is what I wrote after looking at some examples and I am not sure why its not working.
echo $1
if [ $1 != "unset" ]; then
echo "set"
export AMAZON_ACCESS_KEY_ID=XXXXXXXXXXXX
export AMAZON_SECRET_ACCESS_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
export S3_BUCKET_NAME=XXXXXXXXX
else
echo "unset"
export AMAZON_ACCESS_KEY_ID=''
export AMAZON_SECRET_ACCESS_KEY=''
export S3_BUCKET_NAME=''
fi
When running the script it goes to the set section. But when inspecting through echo $AMAZON_ACCESS_KEY_ID # => ''.
I am not sure what is causing the issue. I will be interested in...
A fix for this...
A way to extract and add heroku config variables in the the env in an easier way.
You need to source the script, not run it as a child. If you run the script directly, its environment disappears when it ends. Sourcing the script causes it to be executed in the current environment. help source for more information.
Example:
$ VAR=old_value
$ cat script.sh
#!/bin/bash
export VAR=new_value
$ ./script.sh
$ echo $VAR
old_value
$ source script.sh
$ echo $VAR
new_value
Scripts executed with source don't need to be executable nor do they need the "shebang" line (#!/bin/bash) because they are not run as separate processes. In fact, it is probably a good idea to not make them executable in order to avoid them being run as commands, since that won't work as expected.

How to write a bash script to set global environment variable?

Recently I wrote a script which sets an environment variable, take a look:
#!/bin/bash
echo "Pass a path:"
read path
echo $path
defaultPath=/home/$(whoami)/Desktop
if [ -n "$path" ]; then
export my_var=$path
else
echo "Path is empty! Exporting default path ..."
export my_var=$defaultPath
fi
echo "Exported path: $my_var"
It works just great but the problem is that my_var is available just locally, I mean in console window where I ran the script.
How to write a script which allow me to export global environment variable which can be seen everywhere?
Just run your shell script preceded by "." (dot space).
This causes the script to run the instructions in the original shell. Thus the variables still exist after the script finish
Ex:
cat setmyvar.sh
export myvar=exists
. ./setmyvar.sh
echo $myvar
exists
Each and every shell has its own environment. There's no Universal environment that will magically appear in all console windows. An environment variable created in one shell cannot be accessed in another shell.
It's even more restrictive. If one shell spawns a subshell, that subshell has access to the parent's environment variables, but if that subshell creates an environment variable, it's not accessible in the parent shell.
If all of your shells need access to the same set of variables, you can create a startup file that will set them for you. This is done in BASH via the $HOME/.bash_profile file (or through $HOME/.profile if $HOME/.bash_profile doesn't exist) or through $HOME/.bashrc. Other shells have their own set of startup files. One is used for logins, and one is used for shells spawned without logins (and, as with bash, a third for non-interactive shells). See the manpage to learn exactly what startup scripts are used and what order they're executed).
You can try using shared memory, but I believe that only works while processes are running, so even if you figured out a way to set a piece of shared memory, it would go away as soon as that command is finished. (I've rarely used shared memory except for named pipes). Otherwise, there's really no way to set an environment variable in one shell and have another shell automatically pick it up. You can try using named pipes or writing that environment variable to a file for other shells to pick it up.
Imagine the problems that could happen if someone could change the environment of one shell without my knowledge.
Actually I found an way to achieve this (which in my case was to use a bash script to set a number of security credentials)
I just call bash from inside the script and the spawned shell now has the export values
export API_USERNAME=abc
export API_PASSWORD=bbbb
bash
now calling the file using ~/.app-x-setup.sh will give me an interactive shell with those environment values setup
The following were extracted from 2nd paragraph from David W.'s answer: "If one shell spawns a subshell, that subshell has access to the parent's environment variables, but if that subshell creates an environment variable, it's not accessible in the parent shell."
In case a user need to let parent shell access your new environment variables, just issue the following command in parent shell:
source <your_subshell_script>
or using shortcut
. <your_subshell_script>
You got to add the variable in your .profile located in /home/$USER/.profile
Yo can do that with this command:
echo 'TEST="hi"' >> $HOME/.profile
Or by edit the file with emacs, for example.
If you want to set this variable for all users, you got to edit /etc/profile (root)
There is no global environment, really, in UNIX.
Each process has an environment, originally inherited from the parent, but it is local to the process after the initial creation.
You can only modify your own, unless you go digging around in the process using a debugger.
write it to a temporary file, lets say ~/.myglobalvar and read it from anywhere
echo "$myglobal" > ~/.myglobalvar
Environment variables are always "local" to process execution the export command allow to set environment variables for sub processes. You can look at .bashrc to set environment variables at the start of a bash shell. What you are trying to do seems not possible as a process cannot modify (or access ?) to environment variables of another process.
You can update the ~/.bashrc or ~/.bash_profile file which is used to initialize the environment.
Take a look at the loading behavior of your shell (explained in the manpage, usually referring to .XXXshrc or .profile). Some configuration files are loaded at login time of an interactive shell, some are loaded each time you run a shell. Placing your variable in the latter might result in the behavior you want, e.g. always having the variable set using that distinct shell (for example bash).
If you need to dynamically set and reference environment variables in shell scripts, there is a work around. Judge for yourself whether is worth doing, but here it is.
The strategy involves having a 'set' script which dynamically writes a 'load' script, which has code to set and export an environment variable. The 'load' script is then executed periodically by other scripts which need to reference the variable. BTW, the same strategy could be done by writing and reading a file instead of a variable.
Here's a quick example...
Set_Load_PROCESSING_SIGNAL.sh
#!/bin/bash
PROCESSING_SIGNAL_SCRIPT=./Load_PROCESSING_SIGNAL.sh
echo "#!/bin/bash" > $PROCESSING_SIGNAL_SCRIPT
echo "export PROCESSING_SIGNAL=$1" >> $PROCESSING_SIGNAL_SCRIPT
chmod ug+rwx $PROCESSING_SIGNAL_SCRIPT
Load_PROCESSING_SIGNAL.sh (this gets dynamically created when the above is run)
#!/bin/bash
export PROCESSING_SIGNAL=1
You can test this with
Test_PROCESSING_SIGNAL.sh
#!/bin/bash
PROCESSING_SIGNAL_SCRIPT=./Load_PROCESSING_SIGNAL.sh
N=1
LIM=100
while [ $N -le $LIM ]
do
# DO WHATEVER LOOP PROCESSING IS NEEDED
echo "N = $N"
sleep 5
N=$(( $N + 1 ))
# CHECK PROCESSING_SIGNAL
source $PROCESSING_SIGNAL_SCRIPT
if [[ $PROCESSING_SIGNAL -eq 0 ]]; then
# Write log info indicating that the signal to stop processing was detected
# Write out all relevent info
# Send an alert email of this too
# Then exit
echo "Detected PROCESSING_SIGNAL for all stop. Exiting..."
exit 1
fi
done
~/.bin/SOURCED/lazy script to save and load data as flat files for system.
[ ! -d ~/.megadata ] && mkdir ~/.megadata
function save_data {
[ -z "$1" -o -z "$2" ] && echo 'save_data [:id:] [:data:]' && return
local overwrite=${3-false}
[ "$overwrite" = 'true' ] && echo "$2" > ~/.megadata/$1 && return
[ ! -f ~/.megadata/$1 ] && echo "$2" > ~/.megadata/$1 || echo ID TAKEN set third param to true to overwrite
}
save_data computer engine
cat ~/.megadata/computer
save_data computer engine
save_data computer megaengine true
function get_data {
[ -z "$1" -o -f $1 ] && echo 'get_data [:id:]' && return
[ -f ~/.megadata/$1 ] && cat ~/.megadata/$1 || echo ID NOT FOUND
:
}
get_data computer
get_data computer
Maybe a little off topic, but when you really need it to set it temporarily to execute some script and ended up here looking for answers:
If you need to run a script with certain environment variables that you don't need to keep after execution you could do something like this:
#!/usr/bin/env sh
export XDEBUG_SESSION=$(hostname);echo "running with xdebug: $XDEBUG_SESSION";$#
In my example I just use XDEBUG_SESSION with a hostname, but you can use multiple variables. Keep them separated with a semi-colon. Execution as follows (assuming you called the script debug.sh and placed it in the same directory as your php script):
$ debug.sh php yourscript.php

Bash script exiting prematurely when calling another script inside it

I have a bash script which calls another bash script, like so:
#!/bin/bash
echo "Hi"
./script-two.sh
echo "Hello!"
The problem that I have is that it never makes it to printing "Hello!"
I think this is because ./script-two.sh (Which I did not write) is somehow exiting or changing the shell. I have included this script at the end of this post.
Is there a way I can gurentee that my execution will continue after script-two.sh executes?
I have looked into using the trap command, but I don't fully understand its use properly.
Thanks,
Casey
Here is the contents of what would be script-two.sh
#!/bin/sh
# This file is part of the DITA Open Toolkit project hosted on
# Sourceforge.net. See the accompanying license.txt file for
# applicable licenses.
# (c) Copyright IBM Corp. 2006 All Rights Reserved.
export DITA_HOME=cwd
if [ "${DITA_HOME:+1}" != "1" ]; then
echo "DITA_HOME environment variable is empty or not set";
exit 127;
fi
echo $DITA_HOME
cd "$DITA_HOME"
# Get the absolute path of DITAOT's home directory
DITA_DIR="`pwd`"
echo $DITA_DIR
if [ -f "$DITA_DIR"/tools/ant/bin/ant ] && [ ! -x "$DITA_DIR"/tools/ant/bin/ant ]; then
chmod +x "$DITA_DIR"/tools/ant/bin/ant
fi
export ANT_OPTS="-Xmx512m $ANT_OPTS"
export ANT_OPTS="$ANT_OPTS -Djavax.xml.transform.TransformerFactory=net.sf.saxon.TransformerFactoryImpl"
export ANT_HOME="$DITA_DIR"/tools/ant
export PATH="$DITA_DIR"/tools/ant/bin:"$PATH"
NEW_CLASSPATH="$DITA_DIR/lib:$DITA_DIR/lib/dost.jar:$DITA_DIR/lib/commons-codec-1.4.jar:$DITA_DIR/lib/resolver.jar:$DITA_DIR/lib/icu4j.jar"
NEW_CLASSPATH="$DITA_DIR/lib/saxon/saxon9.jar:$DITA_DIR/lib/saxon/saxon9-dom.jar:$NEW_CLASSPATH"
NEW_CLASSPATH="$DITA_DIR/lib/saxon/saxon9-dom4j.jar:$DITA_DIR/lib/saxon/saxon9-jdom.jar:$NEW_CLASSPATH"
NEW_CLASSPATH="$DITA_DIR/lib/saxon/saxon9-s9api.jar:$DITA_DIR/lib/saxon/saxon9-sql.jar:$NEW_CLASSPATH"
NEW_CLASSPATH="$DITA_DIR/lib/saxon/saxon9-xom.jar:$DITA_DIR/lib/saxon/saxon9-xpath.jar:$DITA_DIR/lib/saxon/saxon9-xqj.jar:$NEW_CLASSPATH"
if test -n "$CLASSPATH"
then
export CLASSPATH="$NEW_CLASSPATH":"$CLASSPATH"
else
export CLASSPATH="$NEW_CLASSPATH"
fi
"$SHELL"
It looks like script-two.sh is setting up an ant build environment.
I think the author intended that it sets up the build environment, then you type your build commands in manually, then type exit to leave the build environment.
I say this because the bottom line of script-two.sh is:
"$SHELL"
which starts a new shell.
Try running your script, then type exit. I think you will see it print Hello! after you type exit.
I'm guessing you're trying to do something like:
#!/bin/bash
echo "Hi"
./script-two.sh
ant <some args>
To do that, what you really want to do is source it, by changing:
./script-two.sh
to
. script-two.sh
e.g.
#!/bin/bash
echo "Hi"
. script-two.sh
ant <some args>
But, you will need to edit script-two.sh and change:
"$SHELL"
to:
case $0 in *script-two.sh)
# executed, start a new shell with the new environment
"$SHELL"
;;
*)
# sourced, don't start a new shell
;;
esac
so that it only starts a shell if the script is being run like ./script-two.sh, but not if it is being sourced like . script-two.sh.
Or if you absolutely can't change script-two.sh, then you could do:
#!/bin/bash
echo "Hi"
. script-two.sh </dev/null
ant <some args>
which will trick "$SHELL" into exiting because it has no input.
Also
export DITA_HOME=cwd
doesn't seem right to me.
It should probably be
export DITA_HOME=$(pwd)
or
export DITA_HOME=`pwd`
(both are equivalent)
I had a similar problem today, up on digging I finally found the answer.
The script I was calling (from within my script) actually had an exit 0 in the end. Removing that fixed my issues.
Just leaving this here as someone may find it useful.
Well for starters, you can execute your bash script with the -x switch to see where it is failing:
bash -x script-one.sh
Secondly, if you call the second script like this:
#!/bin/bash
echo "Hi"
var=$(bash script-two.sh)
echo "Hello!"
It will continue, as long as script-two.sh exits cleanly. Again, you can run the -x script against that script find any problems.
And as Mikel mentioned, always make sure to have exit at the bottom of your scripts.

Resources