echo command
 

this is vinoth. what is the use of echo $? in redhat linux.pls explain it.


regards
vinoth

it returns the exit status of the most recent command run.

you should look up some beginner's books for Linux and shell scripting and read them.

this sounds like homework
look at " man echo " or search google/linux http://www.google.com/linux

Shell uses negative logic.
In general, $? equals 0 denotes the execution of previous command is successful.

The meaning of the exit code 0 can vary depending on the application. By convention, 0 means successful run. This is a convention of app developers more than it is "built in" logic of the shell.

Hi,

In addition to timmeke's reply: Not 0 doesn't necessarily mean the program ran unsuccessful.

Example: Grep can return 1, that tells you grep did not find the pattern given. Which could be what you wanted....

Always look at the manual page/documentation to find out where these numbers stand for.