Error in Shell Scripting

Raise error in a Bash script

This depends on where you want the error message be stored.

You can do the following:

echo "Error!" > logfile.log
exit 125

Or the following:

echo "Error!" 1>&2
exit 64

When you raise an exception you stop the program's execution.

You can also use something like exit xxx where xxx is the error code you may want to return to the operating system (from 0 to 255). Here 125 and 64 are just random codes you can exit with. When you need to indicate to the OS that the program stopped abnormally (eg. an error occurred), you need to pass a non-zero exit code to exit.

As @chepner pointed out, you can do exit 1, which will mean an unspecified error.

Bash script errors out; there are '\r' characters in the execution trace

Line Endings are different on Windows or Linux.

Considering a file

Line A
Line B
Libe C

On Windows it will actually be like

Line A\r\n
Line B\r\n
Libe C\r\n

And on Linux it will be like

Line A\n
Line B\n
Libe C\n

As you can see there is a difference on how the end of a line is defined.

Apparently, you saved your file with Windows Line Ending \r\n so as Linux does not "care" about \r it assumes it's part of the script you are coding... so you are actually executing

#!/bin/bash\r
rsync -trnv /mnt/d/project/bundle/ /mnt/d/bundle/ --exclude=".git" --delete\r
cd /mnt/d/bundle/\r
git add .\r
read -p "" msg\r
git commit -m $msg\r
git push origin master\r
cd "${0%/*}"\r

and that will lead to various problems.

To solve this open the file in an editor and change the line endings.

e.g. in Notepad++

1. Open File
2. Edit -> Eol Conversion -> Unix (LF)
3. Save File

[: missing `]' error in Unix | shell Script

I got the solution

memuse=$ free -m                                                                      
if [ $memuse > 80 ];                                                                  
then                                                                                 
echo "Attention: memory utilisation is high on $(hostname) at $(date)"               
else                                                                                  
echo "Attention : memory utilisation is normal on $(hostname) at $(date)"             
fi 

This is my first time doing bash scripting. So the issue majorly due to the Indentation.

How to catch Spark error from shell script

try like this below example ...

your shell script can catch error code like this... where non zero exit code is error

$? is the exit status of the most recently executed command; by convention, 0 means success and anything else indicates failure.

spark-submit transform_json.py

 ret_code=$?
   if [ $ret_code -ne 0 ]; then 
      exit $ret_code
   fi

You have to code to return exit code by sys.exit(-1) in error condition. check this for python exception handling...

Check this Exit codes in Python

Exception handling in shell scripting?

There is not really a try/catch in bash (i assume you're using bash), but you can achieve a quite similar behaviour using && or ||.

In this example, you want to run fallback_command if a_command fails (returns a non-zero value):

a_command || fallback_command

And in this example, you want to execute second_command if a_command is successful (returns 0):

a_command && second_command

They can easily be mixed together by using a subshell, for example, the following command will execute a_command, if it succeeds it will then run other_command, but if a_command or other_command fails, fallback_command will be executed:

(a_command && other_command) || fallback_command

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