Shell/Bash - Script continues before finishing the line that is running

Question

I have a shell/bash script that works perfectly to make backups, the problem is that I have large files that are giving problems in the execution of the script. The script has to compress the file in the format tar.gz and it does this, but when it arrives at 6GB+or- the script continues to compress the file but passes to the next lines and the backups crashes, the server must have a set_time_limit; same in php, in the php file that calls the shell/bash I use set_time_limit(0); and works very well, the shell/bash has something similar ?

The script:

MYSQLDUMP="$(which mysqldump)"
$MYSQLDUMP -u $DBUSER -h $DBHOST -p$DBPASS $DBNAME | gzip > $TIMESTAMP.sql.gz

ssh $USER_SSH@$HOST_SSH "tar -zcf - $HOME" > $TIMESTAMP.backup.tar.gz

tar -zcf $TIMESTAMP.tar.gz $TIMESTAMP.backup.tar.gz $TIMESTAMP.sql.gz

SUCCESS=$?

rm $TIMESTAMP.sql.gz
rm $TIMESTAMP.backup.tar.gz

I didn’t put the variables in because I don’t think it’s necessary.

Before the end of the tar it removes the 2 files from the end lines ... if the file is less than about 6 GB or 7GB this does not happen

Answer 1

You can ask the SSH client to inform the server that it is active (Alive) each n seconds by inserting the following option:

ssh -o ServerAliveInterval=30 $USER_SSH@$HOST_SSH ...

In this example: 30 seconds. The parameter is -o ServerAliveInterval=<tempo-em-segundos>.

More details here.

Answer 2

There are some alternatives.

One of them is the command timeout.

Executes a command with a time limit, executes the given command and ends if it is still running after the time interval specified.

Where the time limit can be:

• s for seconds (default)

• m for minutes

• h for hours

• d for days

Syntax:

timeout <opções> <duração> <comando> <args..>

Example:

timeout 10 ./script1.py

The above example will run the file script1.py, if after 10s the file is still running, it is closed.

Another alternative is:

./script1.py& sleep 10; kill $!

The line above will run the file script1.py in the background, wait 10 seconds and end the process by specifying the pid in $!.

Editing

You can also in a loop check the return of the function responsible for doing the backup, after the termination ask the user if he wants to proceed with the execution of script or not.

#!/bin/bash

function iniciarBackup(){
    echo "Iniciando backup..."

    MYSQLDUMP="$(which mysqldump)"
    $MYSQLDUMP -u $DBUSER -h $DBHOST -p$DBPASS $DBNAME | gzip > $TIMESTAMP.sql.gz

    ssh $USER_SSH@$HOST_SSH "tar -zcf - $HOME" > $TIMESTAMP.backup.tar.gz
    tar -zcf $TIMESTAMP.tar.gz $TIMESTAMP.backup.tar.gz $TIMESTAMP.sql.gz

    return 0
}

function deletarArquivos(){
    rm "$TIMESTAMP.sql.gz"
    rm "$TIMESTAMP.backup.tar.gz"
}


iniciarBackup

while true ; do
   if [ $? -eq 0 ]; then
     echo "Operação de backup concluída!"
     read -p "Você deseja deletar os arquivos? [S/N]" resposta
     case $resposta in
        [Ss]* ) deletarArquivos; break;;
        [Nn]* ) exit;;
        * ) echo "Você deseja deletar os arquivos? [S/N]";;
    esac
   fi
done

echo "Fim do script."