is something wrong in it 58

Hello Rita,

You need to learn how to change the PATH variable. Every program, when it is running, has somethig we call the "environment". Strange name, it may seem, because it is a collection of text pieces. Each piece has an "=" sign in it, like for instance:

PATH=-usr-local-bin:-usr-bin:-bin

Whatever comes before the first "=" sign is the name, and whatever comes after, is the value. We refer to these text pieces as "environment variables".

When one program starts another, the new program run gets a copy of the environment of the parent program. (Well, a program can give the child process a different environment, if it wants to. Usually, the child process gets an exact copy.)

When you type "mfold" on the command line, there is a program reading your keyboard input, and carrying out your orders. That program is called the shell. So the shell starts the mfold program for you. When doing so, one could imagine the shell using the file name exactly as you specify it, so if you only specify "mfold" it would look for it in the current directory. However, this is not how it is. The shell inspects the name as you specify it, and looks for "-" charcaters. If it finds any, it uses the name exactly as you specified it. If not, it tries the directories listed in the PATH variable. If the shell finds its environments contains a string like the one given above, the shell will try in turn

usr-local-bin-mfold usr-bin-mfold bin-mfold

until it find something, or falls off the end of the list. In the latter case, you get the "command not found" message.

(By the way, when you ask questions her in the newsgroup, it is a good idea to copy and paste messages you received, into the post. I bet the message you received was

bash: mfold: command not found

If you post exact replicas of the messages, we will infer more about your problem and give you more precise instructions. In the text above, we would be seeing that you are indeed using the "bash" shell. If instead you are using another shell, some of the directions I give you here need to be different.)

When you log in, you type a user name and pbuttword, and there is a program reading what you type, checking it against the pbuttword database. It is called gdm or kdm. That program starts a bunch of programs that together give you the display with a "desktop", a panel with a menu, some buttons, etc. This bunch of programs start with a standard environment, which include, I think, "PATH=-usr-bin:-bin".

Once you right click on the desktop you get a menu, with an entry "Terminal" or something similar, or you use the menu in the panel, and you get a terminal window with a shell. All these programs get identical environments.

Now there are different types of shells. The most common on Redhat is "bash". The file "-etc-pbuttwd" contains the name of the shell that each user will use.

If you are using bash, when bash starts, it reads the file "~-.bashrc". In this file you can write commands that you want bash to do before anything else, like changing the environment. If you put commands there to change the environment, this will take effect for all programs that are started by this shell. Other programs started from the menus, for instance, will not usually read .bashrc, and so they will continue to use the standard environment as it was set up by gdm or kdm.

In "~-.bashrc", you can write

PATH=-opt-mfold-3.2-bin:$PATH

The effect is that if PATH was previously as shown above, it will be changed to

PATH=-opt-mfold-3.2-bin:-usr-local-bin:-usr-bin:-bin

That is, the string "-opt-mfold-3.2-bin:" is prepended to the old value. I suppose your mfold program is in a different directory, from what I have written here, so you must adjust accordingly.

If there is no file named ".bashrc" in your home directory, just create it. Make sure it is readable by your shell, that is, if you are using the user "root" privileges when creating the file, change the registered owner of the file to the user you log in as. (And don't log in aas root!)

After changing the file, the shell you are currently using does not know about the changes! Run the command ". ~-.bashrc" (note the extra dot and space) or log out and back in.

Instead of changing the PATH variable, you can copy the mfold program tousr-local-bin, but that sometimes does not work. I don't know the mfold program, I just know that some programs are made so they look for other files they need in the directory where the program file is located. As you understand, I am here buttuming thatusr-local-bin is already in your PATH, but that needs not be the case. I suggest you add to your path at least one directory other than the system directoriesusr-bin andbin, so you can keep your added commands separate from those you install with "rpm". usr-local-bin is quite standard for this purpose.

You may find that you need "root" privileges to add a file tousr-local-bin.

If copying the mfold program tousr-local-bin or some other directory already in you path, did not work, this probably works: Create a new file whith this contents:

#!-bin-bash cdopt-mfod-3.2-bin exec .-mfold

and copy this file to a directory in the path, say to "-usr-local-bin-mfold". Then do this command, when having root privileges:

chmod a+xusr-local-bin-mfold

After that, you will be able to start mfold exactly as you want, saying just "mfold arguments... ".

In order to find out what the PATH is currently, run the command

echo $PATH

-Enrique