You can try the following:

    %set history = 22              (start history)

    %ls *.dat                      (list all data files)

    %history                       (display all events)

    %pwd                           (display current working directory)

    %!!                            (execute last event: pwd)

    %!2                            (execute event #2)

    %!ls                           (execute last event with string "ls")

    %vu moo.dat                    (typo)

    %!!:s/vu/vi/                   (substitute "vi" for "vu" last event)

    %la -ls my*                    (typo)

    %^a^s                          (substitute "s" for "a")

    %!vi                           (execute last event with string "vi")

    %set prompt = '\!%'            (show current prompt number)
    13%                            (what will be displayed to the screen
                                    if you did the above sequence)

Files and Directories

Files

The AIX file system provides a structure where files are arranged in directories, and directories in turn are arranged under other directories in a tree-like organization. Related files can be grouped in directories, of which these "subdirectories" are under the user's primary or root directory.

Files can be accessed by more than one name through the "link" mechanism. Links can be used to make the same file appear in several users' directories, enabling them to share the file easily. More information on this can be found by typing:

The file naming convention in AIX is that all file names can contain up to 14 characters in length, including characters like "." All uppercase and lowercase letters are valid characters, including numbers, the underscore, period and comma. Filename extensions are required for the compilers: a C Language program requires a "c" extension and a FORTRAN program requires an "f" extension. Special characters should be avoided in filenames. These are:

     & ; | * ? \ ' " ` { } ( ) < > $  'space' 'tab'

     \*    gives plain *
    '***'  gives plain ***

Some file commands are:

     cp - Used to copy the contents of one file to another file.
          Syntax:   %cp original file name new file name
          Example:  %cp file1 file2

     mv - Used to rename a file by moving the contents of the file to
          another file.
          Syntax:   %mv original file name new file name
          Example:  %mv file1 file3

     mv - Used to move a file from one directory to another directory.
          This is a useful command for reorganizing the files in your
          directories.
          Syntax:   %mv file name(s) directory name
          Example:  %mv file3 file4 Cprogs
          The two files, file3 and file4, moved from the current working
          directory to the directory Cprogs.

     rm - Used to delete or remove a file permanently.
          Syntax:   %rm original file name
          Example:  %rm file1

     cat - Used to display the contents of a file at the shell prompt.
          Syntax:   %cat file name
          Example:  %cat file3

     pg - Used to display the contents of a file with more than one
          screenfull worth of text, one screen at a time.
          Syntax:   %pg file name
          Example:  %pg file3
          To resume display after each screen is displayed, hit the
          RETURN key.

     more - Like pg, used to display a file one page at a time.
          Syntax:   %more file name
          Example:  %more file3
          To resume display after each screen is displayed, hit the
          SPACE BAR.

Directories

While you are logged into the system, you will always be associated with one directory or another. The "working" directory is the directory that you are currently associated with. To access any file in the working directory, you simply use the name of the file. To access a file in another directory, you must use a pathname. To find out the directory you are currently in, type:

which stands for "print working directory", and the system will display the pathname of the working directory.

Because AIX has a tree-like structure, a file has both a name and a pathname. The absolute pathname is the file's name prefaced with the directory(ies) describing the "path" from the root directory to the file. An example is: /afs/pdc.kth.se/home/u/username/results/run3. The file "run3" is located in a subdirectory "results" that is subordinate to the user's home directory. If you were in the directory "results", then you could access the file by referring to it as "run3".

A file can also be accessed by a relative pathname. Relative pathnames describe the path from the working directory to the file. The special directory ".." refers to the parent of a directory. For example, if the working directory is /afs/pdc.kth.se/home/s/smith/ then ../../j/jones/run3 refers to the file "run3" in the directory afs/pdc.kth.se/home/j/jones/ .

Your "home" directory is the directory you are in at the time you log in. It will hold your startup files and any subdirectories you create. Whenever you create a directory, "mkdir" automatically places two entries into the directory: "." and ".." "." is the directory itself and is synonymous with the path name of the working directory. ".." is the parent directory and is synonymous with the pathname of the parent of the working directory. These directory entries are only visible if you include an option with the list directory command:

Some directory commands are:

     mkdir - Used to create a directory.
          Syntax:   %mkdir ./directory name
          Example:  %mkdir ./fortprogs

     cd - Used to change current working directory to another directory.
          Syntax:   %cd /directory name
          Example:  %cd /projects/fortprogs
                    %cd ..                 (Moves up one directory level)
                    %cd .                  (Change to current directory)

     rmdir - Used to remove a directory.  The directory must be empty.
          Syntax:   %rmdir ./directory name
          Example:  %rmdir ./fortprogs

     pwd - To display to the screen the current working directory.
          Syntax:   %pwd
          Example:  %pwd

File Protection

Utilities

There are many utilities available in AIX, ranging from environment variable changes to processes. A list of popular utilities and a brief description is listed in the appendix section of this tutorial.

Utility programs allow you to work with the system and manipulate the files you create. The following lists the more popular ones.

grep - Used to search through a file to see if it contains a specified
     string of characters.  It displays each line that contains the
     string.
     Syntax:  %grep 'string' file name
     Example: %grep 'subroutine' prog1.f

sort - Used to display the contents of a file in order by lines.  It
     does not change the contents of the file.
     Syntax:  %sort file name
     Example: %sort phonelist

uniq - Used to display a file, skipping adjacent duplicate lines.
     Syntax:  %uniq file name
     Example: %sort phonelist | uniq

diff - Used to compare two files and display a list of the differences
     between them.  This utility does not change the contents of either
     file.  It gives you instructions to add (a), delete (d),
     or change (c) lines in order to convert the first file into the
     second.  Check "man diff" for more information.
     Syntax:  %diff file1 file2
     Example: %diff prog1.jun2 prog2.jun10

Neat AIX Things

Connected to I/O there are several features that are helpful for processing.

Redirection

Redirection describes the various ways you can cause the shell to alter where a command gets its standard input from or where it sends its standard output to. The default standard input and output is the terminal, and this can be "redirected" to a file or another device. An example of output redirected from the terminal and to a file is:

An example of input coming from a file instead of the terminal is:

which sends the contents of the file memo.alex to Alex using mail; mail is receiving input from the file instead of from the terminal.

Pipes and Filters

Pipes can be used to establish a direct connection from the output of one program to the input of another. A pipe is indicated by a "|" between program names or commands.

Filters are utilities that accept data from stdin (standard input) and write to stdout.

Examples of pipes and filters are:

Some popular filters, that are basically utilities are:

     uniq - mentioned earlier, uniq takes an input stream and outputs
          only one copy of any adjacent lines that are identical.

     grep - searches for a pattern and direct any line containing
          the pattern to standard output.

     sort - sorts the lines of a file by a field.

     pg - displays one screen of information at a time, allowing the user
          to view the data before it scrolls.  Similar to "more".

     wc - returns the number of lines, words and characters in a file.

Processes and Aborting Processes

Everything that you do, whether in foreground or in background, is a process. A process is the execution of a command by the AIX system, where a command can be an AIX utility, running a shell script, or just logging on. Processes can be hierarchical, similar to the file structure, which was explained earlier in the tutorial. A parent process can spawn a child process, if so instructed. If a child process is created, it takes over control while executing the command, and the parent process sleeps. The parent process will wake up again after the child process has completed and died.

When using the c-shell (csh), you may also use job control, which allows you to run a process in the background by ending the command with an &. The child process will run in the background without taking control away from the parent process.

You can look at the current processes running in your present session and their status by typing:

This will display the unique process identification number (PID), the parent PID (if there is one), and other information. The command man ps explains the utility in detail. If you wish to stop a process, type:

and process PID will be aborted.

You can look at the current jobs running by typing:

If you wish to put a program in background after it has started, first type ^z (control z) to suspend the program. If you type "jobs" at this point you will see that the job is listed at "stopped". You may then resume the job in the background by typing:

To put a process from background to foreground, type:

where pid is the job number or name as listed by the "jobs" command.

If you wish to terminate program execution in foreground, press the interrupt key (usually ^c). There is a possibility that your key mappings may be different. If ^c does not work for you, contact your system facility administrator for assistance.

Using Mail

An electronic mail system commonly used in AIX is "mail." To write mailfiles, type:

and you will be prompted for the subject. After entering the subject and RETURN, you can then type in your message. Control-D will complete the message and exit you out of the module. You have the option to cc to others after typing your message. If you wish to kill the mail without sending it, enter Control-C twice.

If you wish to read your mail, type:

and you will see header information on all of the mailfile pending reading. To view mail, enter:

    %t                                 (will display the first mail)
or  %t #id of mail to be read        (will display specified mail)

We suggest that you use your local system for electronic mail and set up the forwarding mechanism in case any mail is sent to you on this machine.

Help Facilities

There are several information resources available to users. Please note that while there are some differences between UNIX and AIX, the various documentation also reflects subtle differences.

MAN

The "man" (manual) utility displays to the screen pages from the system documentation. It reflects the AIX operating system. To access, type:

and the information will be displayed.

If you are unsure what the command is that you are looking for, enter:

which will search for keywords in the title lines of the on-line manual. The command

will display more information on the "man" utility. To print man pages you can enter:

ftp filename to the machine where your local printer is attached, and print with the appropriate print command for your facility.

Web pages

View PDC's online information on the World Wide Web at URL:

    http://www.pdc.kth.se/

Editors - Using vi and GNU-Emacs

Make

C Shell and Bourne Shell

References and Other Sources