[dileep]

Hi

While running C Programs in RedHat Linux, i am using the following commands

$ cc Hello.c (it is compiling and giving the binary file a.out)

After that , to run the program I am using the following command

$ a.out

I am getting error as....

bash: a.out: command not found.


How o compile and run C programs???

Thanks in Advance

regards
Dileep

[codejockey]

I suspect the problem is that your PATH does not include the current directory (.). Note that this is standard for the root ID, as to include the current directory in root's PATH is a serious security risk. Try running your program using a command such as: ./a.out and see if results improve.

Hope this helps.

[dileep]

Thank you CodeJockey.

It worked for me.
It gave result without any error.

In UNIX, we say simply a.out
But in LINUX, we say ./a.out

Why is this difference coming between CUI and GUI?

Thanks once again.

regards,
Dileep

[codejockey]

You're welcome for the help. Now, to answer your other questions ...

Both Unix and Linux will allow you to include the current directory in your PATH. If you choose to do so, the current directory will be searched for an executable program that matches the name you specify on the command line (or invoke from a run-box in a GUI such as KDE). I suspect that your PATH under Unix included the current directory but your PATH under Linux did not. You can check this by giving the command:

echo $PATH

at the command line and reviewing the output. If the current directory is included in your PATH, you will see a single period specified between other colon-delimited values. For example, here is the output from echo $PATH on my current system when I am a normal user:

/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/opt/www/htdig/bin:/opt/kde/bin:/usr/lib/qt-3.0.4/bin:/usr/share/texmf/bin:.:/usr/lib

My PATH specifies which directories will be searched to find any executable programs that I invoke. Note that near the end of this string is a single period character between two colon characters; the single period specifies that my current directory should be searched.

In contrast, here is the output of the echo $PATH command on the same system when I am the root user (super-user):

/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/opt/www/htdig/bin:/opt/kde/bin:/usr/lib/qt-3.0.4/bin:/usr/share/texmf/bin:/usr/lib

Note that it does not include a single period between two colons. This means that the current directory will not automatically be searched for an executable invoked by the root user (this is a security safeguard).

Similarly, you may choose either a command-line interface or a GUI interface to interact with the operating system, but this does not affect whether the current directory will be searched for an executable with the name you specify.

Hope this helps.

[dileep]

Thanks for clarifying my doubt.

After that , I tried with the following command

echo $PATH (Logged as Normal User)

it showed me

/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/home/dileepeduri/bin

How should I add PATH ??? that is any path or that period for C programs

Thanks in Advance

regards
Dileep

[codejockey]

Again, you're welcome for any help I've provided. You can modify your PATH in several ways. The syntax varies slightly depending upon which shell you are using (typcially bash, sh or ksh but others are possible). The following example assumes that you are running bash, sh or ksh. To add the current directory to your PATH, you can type:

PATH="${PATH}:."

at the command line. This will add the current directory to the end of your PATH. You can also add this command to a login script such as .bashrc, .profile or .kshrc in your home directory; that way, the command will be executed automatically at each login, and the current directory will be added to your PATH. Your PATH sets the search directories for all commands you attempt to execute, whether those commands are implemented as scripts or compiled executables.

Hope this helps.