Hi,

Recently I have encountered a bug in my Linux kernel.

I am trying to perform the following command in my startup script called example.sh:

echo 1 > /var/opt/lab/example.log

5 out of 100 times in my Syslog I captured:

It shows me this error:

/usr/bin/example.sh: line 494: /var/opt/lab/example.log : Is a directory

From my understanding, i dont think this is possible.

I hope anyone can share some ideas with me.

I have two scripts called script A and script B let's say:
######################################Script A#################################
The logic in my script is this:
i will provide more detail here:
every time restart I need to check a flag file called flag which is in the same directory /var/opt/lab/
this flag only used once, once it's been detected i will do

if [ -d "/var/opt/lab/flag" ]; then
rm -rf /var/opt/lab/*
echo "Delete Factory files."
fi

then I also do:

if [ ! -d "/var/opt/lab/" ]; then
mkdir -p /var/opt/lab
echo "/var/opt/lab created"
else
echo "/var/opt/lab already exists"
fi

during normal operation the flag file is deleted then :
VALUE can be either 0 or 1 depends on the register value I read

echo "${VALUE}" > /var/opt/lab/example.log

##################Script B###################################
INDEX=`cat /var/opt/lab/example.log` ---------------------------------------------------> This is where the error raised: says it's a directory not a file

Based on the INDEX i will do different operations.
###########################################################################

[QUESTION]I can not determine where does this example.log directory comes from I need tips on trouble shoot this. Is it linux kernel driver related ?

Best Regards,
Jiye

&
are two different things

Well, it is quite possible that /var/log/lab/example.log is a directory. For example:
and voila, /var/log/lab/example.log is a directory.

The question is, where does this directory come from. I can't tell.

In your script, you could add code like this:

Ha! I didn't catch this.

One is /var/log/lab. The other, /var/opt/lab. I assume that the space before example.log is a typo.

echo 1 > /var/log/lab/example.log is called from line 494 of my example.sh script

sorry it's a typo should be echo 1 > /var/opt/lab/example.log

yes, it's a typo and I already fixed it.

yes that is my really confusion I want to address here, how comes it can be a directory if I only generated it as a file?

to expand on what @berndbausch has already said, refer to this : https://www.tldp.org/LDP/abs/html/fto.html

and a 'ls -l' should tell you if it is a directory or a file.

my question here is not to determine if it's a directory or a file.

I am trying to seek for the solution of why the file system generates a directory when I actually created a file

Sorry, but is it /var/log/lab/example.log or /var/opt/lab/example.log now? In your script?
And are you sure there isn't a space between /var/.../lab/ and example.log, like so: ???

Impossible to say anything further without knowing what else has access to that file. I assume you have "anonymised" that output for us?
Are you using /var/.../lab/example.log only once throughout the whole script, just to echo a "1" into it?
What else uses this file? What does it log?

It's /var/opt/lab/example.log now
Was a typo and I fixed it
(1) There is no space /var/opt/lab/example.log
(2)
The logic in my script is this:
i will provide more detail here:
every time restart I need to check a flag file called flag which is in the same directory /var/opt/lab/
this flag only used once, once it's been detected i will do

if [ -d "/var/opt/lab/flag" ]; then
rm -rf /var/opt/lab/*
echo "Delete Factory files."
fi

then I also do:

if [ ! -d "/var/opt/lab/" ]; then
mkdir -p /var/opt/lab
echo "/var/opt/lab created"
else
echo "/var/opt/lab already exists"
fi

during normal operation the flag file is deleted then :
VALUE can be either 0 or 1 depends on the register value I read

echo "${VALUE}" > /var/opt/lab/example.log
INDEX=`cat /var/opt/lab/example.log` ---------------------------------------------------> This is where the error raised: says it's a directory not a file

Based on the INDEX i will do different operations.

please.

And no other process ever accesses/writes to /var/opt/lab/ and/or /var/opt/lab/example.log???

Since you are creating that directory in your script, it is really very likely that you did something wrong in your script.

Do more troubleshooting, e.g.:

1. add
as the 2nd line of your script (right under the #!/bin/bash).

2. Try saving example.log to another directory, one you do not constantly create/delete.

Would be great if you can explain what does set -xv do in this case.

Searching for bash "set -xv" returns the relevant part of the Bash manual, along with plenty of other results which answer this.

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