System Administration Guide: Advanced Administration

Chapter 19 Troubleshooting File Access Problems (Tasks)

This chapter provides information on resolving file access problems such as those related to incorrect permissions and search paths.

This is a list of troubleshooting topics in this chapter.

Users frequently experience problems, and call on a system administrator for help, because they cannot access a program, a file, or a directory that they could previously use.

Whenever you encounter such a problem, investigate one of three areas:

This chapter briefly describes how to recognize problems in each of these three areas and suggests possible solutions.

Solving Problems With Search Paths (Command not found)

A message of Command not found indicates one of the following:

To fix a search path problem, you need to know the pathname of the directory where the command is stored.

If the wrong version of the command is found, a directory that has a command of the same name is in the search path. In this case, the proper directory may be later in the search path or may not be present at all.

You can display your current search path by using the echo $PATH command. For example:

$ echo $PATH 

Use the which command to determine whether you are running the wrong version of the command. For example:

$ which acroread 

Note –

The which command looks in the .cshrc file for path information. The which command might give misleading results if you execute it from the Bourne or Korn shell and you have a .cshrc file than contains aliases for the which command. To ensure accurate results, use the which command in a C shell, or, in the Korn shell, use the whence command.

ProcedureHow to Diagnose and Correct Search Path Problems

  1. Display the current search path to verify that the directory for the command is not in your path or that it isn't misspelled.

    $ echo $PATH 
  2. Check the following:

    • Is the search path correct?

    • Is the search path listed before other search paths where another version of the command is found?

    • Is the command in one of the search paths?

    If the path needs correction, go to step 3. Otherwise, go to step 4.

  3. Add the path to the appropriate file, as shown in this table.





    Bourne and Korn 


    $ PATH=$HOME/bin:/sbin:/usr/local /bin ...

    $ export PATH

    A colon separates path names. 




    hostname% set path=(~bin /sbin /usr/local/bin ...)

    A blank space separates path names. 

  4. Activate the new path as follows:


    File Where Path Is Located 

    Use this Command to Activate The Path 

    Bourne and Korn 


    $ . ./.profile


    hostname% source .cshrc



    hostname% source .login

  5. Verify the new path.

    $ which command

Example 19–1 Diagnosing and Correcting Search Path Problems

This example shows that the mytool executable is not in any of the directories in the search path using the which command.

venus% mytool
mytool: Command not found
venus% which mytool
no mytool in /sbin /usr/sbin /usr/bin /etc /home/ignatz/bin  .
venus% echo $PATH
/sbin /usr/sbin /usr/bin /etc /home/ignatz/bin
venus% vi ~/.cshrc
(Add appropriate command directory to the search path)
venus% source .cshrc
venus% mytool

If you cannot find a command, look at the man page for its directory path. For example, if you cannot find the lpsched command (the lp printer daemon), the lpsched(1M) man page tells you the path is /usr/lib/lp/lpsched.

Solving File Access Problems

When users cannot access files or directories that they previously could access, the permissions or ownership of the files or directories probably has changed.

Changing File and Group Ownerships

Frequently, file and directory ownerships change because someone edited the files as superuser. When you create home directories for new users, be sure to make the user the owner of the dot (.) file in the home directory. When users do not own “.” they cannot create files in their own home directory.

Access problems can also arise when the group ownership changes or when a group of which a user is a member is deleted from the /etc/group database.

For information about how to change the permissions or ownership of a file that you are having problems accessing, see Chapter 6, Controlling Access to Files (Tasks), in System Administration Guide: Security Services.

Recognizing Problems With Network Access

If users have problems using the rcp remote copy command to copy files over the network, the directories and files on the remote system may have restricted access by setting permissions. Another possible source of trouble is that the remote system and the local system are not configured to allow access.

See Strategies for NFS Troubleshooting in System Administration Guide: Network Services for information about problems with network access and problems with accessing systems through AutoFS.