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Adding some more information

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edited May 21, 2020 at 21:39

Update

Here are answers to questions in the comments below..

This screenshot shows me running both scripts. Each time the minisatip process was running and the enigma2 process was not running.

The path of the first script, the one with just 3 or 4 lines, is /home/root/test.sh and I can run it from anywhere, it seems, simply like this # test.sh
The path of the second script is /usr/bin/enigma2.sh and as you can see I run it simply like enigma2.sh

As suggested I updated both scripts to remove the wc and awk from the piped command whose output is meant to assign a value to the variable: ENIGMA_PID

I changed /home/root/test.sh to this:

#!/bin/sh
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep)
echo $ENIGMA_PID
echo "$ENIGMA_PID"

And in /usr/bin/enigma2.sh I added these lines to the top of the script...

#!/bin/sh
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep)
echo $ENIGMA_PID
echo "$ENIGMA_PID"

# Check if the no_enigma file exists
...
....

Now I ran the scripts and this screenshot shows the output..

The process I am checking for is a binary with path: /usr/bin/enigma2. This binary is not running. Yet, when the enigma2.sh script runs there are two process ids. Is this because the script itself is called enigma2? Well then why are their two process ids called enigma2 and not one?

Question
What do I need to change in this command
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep|wc -l | awk '{print $1}')

... when it's in a script called /usr/bin/enigma2.sh
... so it doesn't count the script, it is a part of, as a running process?
... the result should be ZERO if the binary /usr/bin/enigma2 is not running.

Thank you!

Flex

Update

Here are answers to questions in the comments below..

This screenshot shows me running both scripts. Each time the minisatip process was running and the enigma2 process was not running.

As suggested I updated both scripts to remove the wc and awk from the piped command whose output is meant to assign a value to the variable: ENIGMA_PID

I changed /home/root/test.sh to this:

#!/bin/sh
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep)
echo $ENIGMA_PID
echo "$ENIGMA_PID"

And in /usr/bin/enigma2.sh I added these lines to the top of the script...

#!/bin/sh
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep)
echo $ENIGMA_PID
echo "$ENIGMA_PID"

# Check if the no_enigma file exists
...
....

Now I ran the scripts and this screenshot shows the output..

Question
What do I need to change in this command
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep|wc -l | awk '{print $1}')

Thank you!

Flex

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asked May 20, 2020 at 23:47

FlexMcMurphy

Why does this variable assigned ZERO have the value TWO

I am trying to create a script that populates a variable with zero when a process called 'enigma2' does not exist.

When I run this script...

#!/bin/sh
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep|wc -l | awk '{print $1}')
echo $ENIGMA_PID
echo "$ENIGMA_PID"

I get the output...

0  
0

Which is what I expect.

But when I run this script:

#!/bin/sh

# Check if the no_enigma file exists
if [ -f /home/root/no_enigma ]; then
    # If enigma2 is running then kill it
    ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep|wc -l | awk '{print $1}')
    echo $ENIGMA_PID
    echo "$ENIGMA_PID"

    re='^[0-9]+([.][0-9]+)?$'
    if ! [[ $ENIGMA_PID =~ $re ]] ; then
       echo "error: Not a number" >&2; exit 1
    else
        echo "It IS a number"
    fi
    
        if [ "$ENIGMA_PID" -gt 0 ]; then
            echo $ENIGMA_PID
            echo "$ENIGMA_PID"
            echo "enigma2 is running"
            killall enigma2
        else
            echo "enigma2 is not running"       
        fi
    # Check if minisatip is running already, if not then start it
    MINI_PID=$(ps ax|grep minisatip|grep -v grep|wc -l | awk '{print $1}')
        if [ "$MINI_PID" -gt 0 ]; then
            echo "minisatip is already running"
        else
            echo "minisatip is not running"
            echo "starting minisatip"
            /usr/bin/minisatip --satip-xml http://127.0.0.1:8554 -R /usr/share/minisatip/html       
        fi
else
    # The no_enigma file does not exist
    # Check if minisatip is running, if yes then kill it
    MINI_PID=$(ps ax|grep minisatip|grep -v grep|wc -l | awk '{print $1}')
        if [ "$MINI_PID" -gt 0 ]; then
            echo "minisatip is running, killing it now"
            killall minisatip
        else
            echo "minisatip is not running"
        fi  
    # Check if enigma2 is running already, if not then start it
    ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep|wc -l | awk '{print $1}')
        if [ "$ENIGMA_PID" -gt 0 ]; then
            echo "enigma2 is already running"
        else
            echo "enigma2 is not running"
            echo "starting enigma2"
            /home/root/run_enigma.sh            
        fi
fi

I get this output...

2  
2  
It IS a number  
2  
2  
enigma2 is running  
killall: enigma2: no process killed  
minisatip is already running

If I remove #!/bin/sh from the top of the second script I get the expected output..

0  
0  
It IS a number  
enigma2 is not running  
minisatip is already running

Why do these three lines:

#!/bin/sh
ENIGMA_PID=$(ps ax|grep enigma2|grep -v grep|wc -l | awk '{print $1}')
echo $ENIGMA_PID
echo "$ENIGMA_PID"

Correctly report the $ENIGMA_PID variable as having value 0
But in the second script those same three lines report the $ENIGMA_PID variable as having value 2?

Flex