We got a script that we need to understand, and at some point, we got this syntax: if  [ $PASS_CHAINE = TRUE ]then echo Launching DEGAGEMENT | SLog     cd $INTERFACE_D/bin_cm/deg     $INTERFACE_D/bin_cm/deg/lance_deg 2>&1 ; echo {@@##}RETURN_REAL_STATUS_SCRIPT=${?} | SLog     EXIT_CODE=$?     if [ $EXIT_CODE -ne 0 ]     then echo Error in DEGAGEMENT | SLog          exit_script     fi fiI'm confused about the echo {@@##} part, I don't really understand it.I know the scripts tries to test the return code of the lance_deg function, but it won't work because it's gonna get the return code of the echo command.I can remove the echo part to solve my problem, but the point is really to understand what the {@@##} part means.
What means echo{@@##}?
bash;shell script
That part:echo {@@##}RETURN_REAL_STATUS_SCRIPT=${?}Just prints:{@@##}RETURN_REAL_STATUS_SCRIPT=xwhere the last x is replaces by the value of variable $?. From the bash manpage:   ?      Expands to the exit status of the most recently executed foreground pipeline.That means that $? contains the exit code of the previously executed command: $INTERFACE_D/bin_cm/deg/lance_deg, which can be a digit from 0; for success and 1 or geather for an error.See this:$ ls filefile$ echo $? # 0 indicates success0$ ls file_not_existls: cannot access file_not_exist: No such file or directory$ echo $? # >0 is an error2