HP 3000 Manuals HP 3000 Manuals
New CI Commands
by Bellos Nisan
Commercial Systems Division
Product Overview
Releases 4.5 and 5.0 of MPE/iX provide POSIX standard functionality as an
integral part of the MPE operating system. As a result UNIX and POSIX
compliant applications can run on MPE/iX with little or no change.
MPE/iX has been designed so that the existing interfaces (such as
intrinsics and CI commands) can refer to all the objects in the directory
without changing the way they refer to the MPE objects such as files in
groups. Also, POSIX interfaces such as POSIX.1 functions and POSIX.2
commands are able to refer to MPE objects such as accounts and groups and
files within them. It is important to note that MPE applications and
scripts that executed successfully prior to release 5.0 will continue to
function correctly in release 5.0.
To manage and utilize this new functionality several CI commands have
been added and many old commands have been enhanced. The focus of this
article is on the Command Interpreter (CI) changes and additions.
Hierarchical File System (HFS)
Overview.
The MPE operating system had been designed primarily for use in a
department setting. All the users in a particular department are
typically grouped together and placed in one account. Similarly, an
account, such as PAYROLL, could organize its files in groups such as
JAN92, FEB92, and so on. In this model, the directory tree consists of
one or more accounts, with each account containing one or more groups or
directories. Finally, each group has zero or more files in it. Hence,
this file.group.account structure can be looked at as a 3-level
hierarchical structure. The first level has account entries, the second
level group entries, and the third level the actual files. POSIX,
however, has an expanded version of MPE hierarchy. The POSIX directory
structure has a root directory, which is represented by a slash (/). The
root directory may have files and directories under it. The directories,
in turn, have files and directories under them. MPE/iX has integrated
the MPE and POSIX concepts resulting in the new HFS. A typical MPE/iX
directory may look like:
/
|
+---------------------+------+----------------------------+
| | |
PAYROLL DEVELOP users
| | |
+---+---+ +------+--------+ +---+---+
| | | | | | |
JAN92 FEB92 MyDir MyFile PXGROUP bruna jeff
| | | |
+---+---+ FileOne +------+------+--------+ +---+---+
| | | | | | | |
HOURS TAXINFO data ledger payable PRGFILE bin addr_bk
| |
+---+---+ +------+-------+
| | | | |
main.c Makefile my_ls FILES down_load
|
+------+------+
| | |
file1 file2 file3
This directory structure will be the basis of our examples throughout
this article.
On MPE/iX the root directory may contain files, directories, and
accounts. Accounts and groups are treated as special directories. For
example, groups and accounts cannot be purged by the PURGEDIR command
which is discussed later on in this article. Also, groups and accounts
contain additional information such as capabilities and limits.
Hierarchical File System (HFS) directories do not contain such
information.
The POSIX implementation allows for the creation of directories and files
under accounts and MPE groups. In our example directory structure above,
the PAYROLL account is a normal MPE account containing two groups JAN92
and FEB92. On the other hand the account DEVELOP contains a group
PXGROUP, a subdirectory MyDir, and a file MyFile. The group PXGROUP
contains two files data, and PRGFILE, and two subdirectories ledger and
payable. The directory users is created immediately under the root
directory. This directory contains two subdirectories bruna and jeff.
The directory jeff has a simple file addr_bk, two subdirectories bin and
FILES.
Here are the highlights of the MPE/iX directory structure:
* The root directory (represented by a slash ("/")) can have
accounts, directories, or files under it.
* All directories can have files or directories under them.
* MPE accounts can have groups, files, and directories under them.
* MPE groups can have files or directories under them.
* Only accounts and groups must have valid MPE names. All other
objects can use the portable HFS character set that consists of
A-Z, a-z, 0-9, and three special characters dot ("."), hyphen
("-"), and underscore ("_"). Object names cannot start with a
hyphen ("-").
* All names below the root, account, and directories under MPE
groups can be at most 16 characters in length. Note that account
and group names must be valid MPE names. All other names can be
up to 255 characters long (see explanation about the CI buffer
size changes in the MISCELLANEOUS ENHANCEMENTS section below).
Creating a Directory.
A new CI command NEWDIR can be used to create a new directory. By
default, it assumes MPE naming rules unless the name specified is
preceded by a dot (".") or slash ("/") denoting that POSIX naming rules
should be applied to the filename. Directories can be created directly
below the root, another directory, account, or a group object. Normally,
HFS names can be as long as 255 characters except when creating
directories directly below a group, account, or the root directory, in
which case their name length cannot exceed 16 characters. Only files and
directories directly below a directory can have longer names. To be able
to create a new directory under an object the user must have CD (Create
Directory entry) access to that object. For example, suppose that a user
logs on as following:
:hello ledger, engineer.develop, pxgroup
The user engineer can enter the following command to create a directory
under his/her CWD.
:newdir testdir
Note that because MPE naming rules are used by default, the name testdir
is upshifted to TESTDIR before that directory is created.
To create a directory with lower case or mixed case letters, the CI must
be instructed to use POSIX naming rules. That is accomplished by
preceding the directory name by a dot (".") or slash ("/") to denote
MPE-escape syntax. For example,
:newdir ./ledger
A restriction on MPE-escaped names is that they cannot be longer than 16
characters when the CWD is not a directory. The following example fails
because the name is longer than 16 character.
:newdir ./a_long_directory_name
Changing Current Working Directory (CWD).
The new CHDIR command allows users to change their CWD. When CHDIR is
issued without any parameters, it changes the CWD to user's logon group.
If the user engineer.develop wants to work in the ledger directory under
the group PXGROUP, the CWD can be changed using a relative pathname as
following:
:chdir ./ledger
Another way of doing the same is through using an absolute pathname as
following:
:chdir /DEVELOP/PXGROUP/ledger
It is possible to change the CWD to any directory as long as you have
proper access. If the user engineer.develop has TD (Traverse Directory
entry) access to the root (/), users, and jeff directories, the following
command changes the CWD to /users/jeff.
:chdir /users/jeff
Note that when the CHGROUP command is issued it causes the CWD to be
changed to the new logon group. However, when a CHDIR command is issued
it does not affect the logon, and it does not affect file access security
at all.
Purging a Directory.
MPE/iX provides a new command PURGEDIR to purge a directory. Suppose
that a user has just logged on as following:
:hello ledger, engineer.develop, pxgroup
The user can purge the directory payable as following:
:purgedir ./payable
However, the command
:purgedir ./ledger
does not succeed because the directory ledger is not empty - it contains
two files main.c and Makefile under it. To purge the directory ledger
and everything below it, the following command should be used instead:
:purgedir ./ledger; tree
Although groups and accounts are treated as special directories, the
PURGEDIR command cannot be used to purge them.
Symbolic Links
This section discusses CI commands to manage symbolic links. For
information on symbolic linking concepts refer to Ali Shehk's article
"Symbolic Links on MPE/iX" in this Communicator.
Creating a Symbolic Link.
Release 5.0 provides a new CI command NEWLINK to create a symbolic link
to a file, group, account, root or another directory. Suppose that a
user logs on as following:
:hello sabrina, engineer.develop, pxgroup
The user sabrina can create a symbolic link SYMLN and associate it with
the target file TAXINFO.FEB92.PAYROLL as following:
:newlink symln, taxinfo.feb92.payroll
or
:newlink ./SYMLN, /PAYROLL/FEB92/TAXINFO
This creates a file called SYMLN under group PXGROUP of account DEVELOP.
Assuming that the user sabrina has appropriate access to the target file,
she can use the print command to examine the contents of the target file
as following:
:print symln
instead of
:print taxinfo.FEB92.payroll
The power of symbolic links becomes apparent when you want to move a set
of files from one location to another due to, say, software distribution.
You certainly do not want to affect the normal processing of any
application that accesses those files. To accomplish this task you can
move the actual files to the new location, and in the old location create
symbolic links with the same name specifying the CWD(s) of the new
location of the files.
For example, suppose that files file1, file2, and file3 originally
existed under the group PXGROUP of account DEVELOP. As part of
some housekeeping activity you decided to move the files to
/users/jeff/bin/FILES directory. Now to ensure that all the applications
that access those files still function properly, you must create symbolic
links to those files as following:
:chdir /DEVELOP/PXGROUP
:newlink ./file1, /users/jeff/bin/FILES/file1
:newlink ./file2, /users/jeff/bin/FILES/file2
:newlink ./file3, /users/jeff/bin/FILES/file3
From this point on any time an application accesses these files, the
symbolic links redirect the file system to the new location of the files.
Please note that this only applies to commands that operate on the target
of the links and not links themselves. For example, PURGELINK and STORE
operate on the link itself and not the target files. You can use this
method to install newer versions of these files in another location
without overlaying their current version, and changing the symbolic links
to point to the newer version. If at any time you need to access the old
version, you can point the symbolic links to that version of the files.
Purging a Symbolic Link.
To remove a symbolic link, release 5.0 includes a new command named
PURGELINK. It takes the name of a symbolic link and purges it without
affecting the target of that link. For example if user sabrina wishes to
remove a symbolic link SYMLN, she can enter the following:
:purgelink symln
or
:purgelink ./SYMLN
System Clock
Setting the System Clock.
The SETCLOCK command is a new CI command provided to easily alter the
system date, time, or time zone. You no longer have to reboot the system
in order to set the system date and time. For example, to change the
system date and time to December 6, 1993, 7:00 pm enter the following
command:
:setclock 12/06/1993, 19:00
This causes the system clock to speed up until the desired date and time
are achieved without out-of-sequence log file time stamps. It is
possible to force the command to take effect immediately by specifying
the NOW option, however you must understand the ramifications of forcing
a new date or time on the scheduled jobs and other processing before
using this option.
This command is available to users with DI and either SM, or OP
capability. Additionally, SM capability is required to use the NOW
option. For more information on setting the system clock, refer to the
following articles in this Communicator:
* "Introducing SETCLOCK and SHOWCLOCK, Two New CI Commands"
* "Using the SETCLOCK Command"
Displaying the System Clock.
To view the system clock the CI provides a new command named SHOWCLOCK.
It displays information about system date, time, time correction, and the
time zone.
Altering a Directory or a File's Attributes
The ALTFILE command is used to alter a file's characteristics. Currently
the attributes that can be modified are the owner (UID) and POSIX group
(GID) of a file, directory, MPE group or account, with the restriction
that the GID may not be altered for MPE groups or accounts.
To change the UID of a file, you must be one of the following:
* The file's account manager (a user whose logon account matches the
GID of the file and has AM capability)
* A system manager (a user who has SM capability)
To change the GID of a file, you must be one of the following:
* The file owner (a user whose logon name matches the UID of the
file)
* The file's account manager (a user whose logon account matches the
GID of the file and who has AM capability)
* A system manager (a user who has SM capability)
Suppose that you are the account manager of file TAXINFO.FEB92.PAYROLL,
and you want to change its GID to DEVELOP so that it can be accessible by
users of the DEVELOP account. You may log on to the PAYROLL account and
use ALTFILE as follows:
:altfile taxinfo.FEB92; groupid=DEVELOP
Disk Space Management
Viewing Disk Space Usage.
MPE/iX Releases 4.5 and 5.0 provide a new CI command DISKUSE to report
the disk space usage of directories, groups, and accounts. Note that
DISKUSE is not a replacement for the REPORT command. The REPORT command
must be used to view the CPU usage and connect time attributes associated
with a logon.
To see the total disk space used by the entire directory structure enter
the following command:
:diskuse /
This command shows the total space used by the root directory and
everything below it. It breaks it up further to show the disk space used
by each directory node. If you do not want to see the disk space used by
each directory and wanted to see just the grand total, use the following
command:
:diskuse /; notree
To see the disk space used by each group in the DEVELOP account, and the
total space used by all these groups (which do not include the disk space
used by the account node DEVELOP itself), issue the following command:
:diskuse /DEVELOP/@; tree
New CI Variables.
Three new read only system variables HPCWD, HPFILE, and HPPIN have been
added to release 5.0.
HPCWD is a string type variable that contains your current working
directory. To alter the CI prompt to display the pathname of your CWD
you may enter the following command:
:setvar hpprompt "!!HPCWD> "
If you are logged on to group JAN92 in account PAYROLL the CI prompt for
your session displays "/PAYROLL/JAN92>". If you use the CHDIR command to
move to the FILES subdirectory under /users/jeff/bin the prompt is
changed to "/users/jeff/bin/FILES> ". Like all CI string variables,
HPCWD is limited to a maximum of 255. If your CWD pathname exceeds this
limit, CIERR 8159 is returned.
HPFILE is a string type variable that contains the fully qualified MPE
name of the currently executing UDC file or command file. This variable
does not track the name of a stream job and it is set to null string
(length = 0) at all times except when a UDC file or command file is
executing.
HPPIN is an integer type variable that contains the process
identification number (PIN) of the currently executing process. This
variable may be used to construct a unique filename within a commonly
used directory such as /tmp. For example:
:build /tmp/myfile!hppin
New FINFO Item Numbers
Several new item numbers have been added to the FINFO function of the CI
as well as enhancing it to recognize POSIX syntax. The new item numbers
range from 38 to 53 and return information such as name of a file in
POSIX syntax, UID and GID of a file or directory, device type, file type,
file size in bytes, and whether a file is secured or released. For a
complete description of these new items and what they represent consult
the MPE/iX Commands Reference Manual (32650-90003).
Enhancements to Commands
STORE Enhancement.
The STORE command has been enhanced to translate wilcarded MPE syntax
names to include all files (all MPE files and all HFS files and
directories) as follows:
@.group.account => /ACCOUNT/GROUP/ (all files under GROUP.ACCOUNT)
@.@.account => /ACCOUNT/ (all files under ACCOUNT)
@.@.@ => / (all files on the system)
@.@ => /logon account/ (all files under logon account)
@ => ./ (all files under current directory)
For more information refer to the article "TURBOSTORE/iX Changes" in this
Communicator.
PURGE Changes.
In this release of MPE/iX the PURGE command has been moved to native mode
and has been enhanced to accept wildcards so that multiple files may be
removed at once.
The migration of the command from compatibility to native mode allows it
to benefit from the central parsing system that is used by other native
mode commands such as PRINT, COPY, and NEWDIR. It also entails that the
command ignores trailing delimiters as do all native mode commands. This
means that the following scenario does not exist on MPE/iX.
:hello manager.payroll, feb92
:build hours; temp
:purge hours,
^
Expected TEMP. (CIERR 382)
Instead of producing an error, the permanent file HOURS.FEB92.PAYROLL is
deleted.
The addition of wildcards allows the command to remove multiple files at
once. Several options are provided to control the behavior of the
command so that accidental deletion of files may be avoided. Here is an
example of using the new wildcard feature:
:purge /users/jeff/bin/FILES/file@
3 FILEs matched
Continue PURGE ? (YES/NO)yes
3 selected. 3 succeeded. 0 failed.
To remove a number of files one at a time in an interactive mode so that
you can skip a file or completely stop the processing of the command, you
may use the CONFIRMALL option as follows:
:purge /users/jeff/bin/FILES/file@; confirmall
3 FILES matched
/users/jeff/bin/FILES/file1 ? (NO/YES/QUIT)yes
/users/jeff/bin/FILES/file2 ? (NO/YES/QUIT)no
/users/jeff/bin/FILES/file3 ? (NO/YES/QUIT)yes
2 selected. 2 succeeded. 0 failed.
Enter "q" or "quit" or press the BREAK key in response to the query if
you decide to stop the processing of the command altogether.
Let us consider a more common example of the use of the PURGE command.
Enter the following command and observe its output:
:purge log#@
10 FILES matched
Continue PURGE ? (YES/NO)yes
10 selected. 9 succeeded. 1 failed.
Since the PURGE command does not remove the currently open log file, the
command always returns "1 failed".
The PURGE command cannot be used to remove special files such as
directories or symbolic links.
LISTFILE Changes.
The LISTFILE command has been enhanced to show file information for both
the MPE and the POSIX syntax. The new POSIX displays support all the
formats currently allowed by LISTFILE. To see these new formats simply
issue the LISTFILE command specifying the filename using MPE-escaped
syntax.
The MPE formats are backward compatible with the release 4.0 formats
except for the following:
A. Formats 5 and 7 add two new fields COMPUTE BLK SIZE and VERSION
for KSAM type files, and
B. There are no continuation headers and page breaks on long listings
for formats -2, 1, and 2, and
C. To correct a problem, a minor change has been made to the display
of format 4. When more than four access subjects are assigned to
either READ, WRITE, and APPEND access lists of a file, display of
the FCODE: #, **SECURITY IS ON/OFF, and NO ACDS/ACD EXISTS is
shifted to the right by seven characters. Release 4.0 display
format is retained at all other times.
In addition formats 1 and 2 use additional characters in the TYP column
of the file being displayed. The TYP column can contain up to four
characters as described below:
1. First character indicates a file's record type as follows:
F : Fixed
V : Variable
U : Undefined
A : Account
G : Group
B : Byte stream
H : Hierarchical directory
2. Second character indicates "A" for ASCII, or "B" for binary
3. Third character indicates CCTL or NOCCTL. When CCTL a character
"C" appears in the third location. Otherwise nothing is added
causing the fourth character to appear in the third location.
4. Fourth (third if no CCTL) character indicates the file type as
follows:
R : Relative IO file
K : Native mode KSAM file
O : Circular file
S : Spool file
M : Message file
D : Directory
f : FIFO file
L : Symbolic link file
d : Device link file
s : Streams device file
Note that FIFO and Device Link file indicators are lowercase
characters.
Since some of the characters like "B" are used to indicate different
attributes, their character position is significant. That is, a "B" in
the first location always means BYTE-STREAM and not BINARY. Likewise, a
lowercase "d" is different from its uppercase counterpart "D" when it
appears in the third or the fourth location.
For example, consider the following segment of a LISTFILE output:
FILENAME CODE ------------LOGICAL RECORD----------- ----SPACE----
SIZE TYP EOF LIMIT R/B SECTORS #X MX
DIR 16W HBD 0 67107839 1 32 1 *
FIFO 128W BBf 0 1 1 0 0 *
FIFOC 128W BBs 0 1 1 0 0 *
KSAM 128W FBK 0 1023 1 320 2 *
SPOOL1 OUTSP 1008B VAS 0 1023 1 0 0 *
SPOOL2 OUTSP 1008B VACS 15 1 1 16 1 *
SYMLINK 1B BAL 6 1024 1 16 1 *
Note that the FIFO and FIFOC files' TYP column starts with "BB".
Remember that the first "B" means BYTE-STREAM and the second "B" means
BINARY. Furthermore, the spool file SPOOL1 was created without CCTL,
whereas spool file SPOOL2 was created with CCTL, thus for file SPOOL2 the
CCTL indicator "C" was inserted in its appropriate position causing the
spool file indicator "S" to be shifted to the right.
Note that when you issue the LISTFILE command without any parameters, it
defaults to searching for uppercase names in your CWD. Your CWD may or
may not be the same location as your logon group and account. Therefore,
do not assume that unqualified names will be fully qualified by the
system by appending .logongroup.logonaccount to them. Also, LISTFILE and
LISTF display all names that adhere to the MPE naming conventions
regardless of the way they were created. For example, LISTFILE displays
the name of the file created using the following command:
:build ./MPEVALID
But it does not display the name of the following file since it is more
than 8 characters long.
:build ./LONGUPCASENAME
Additionally, LISTFILE has been enhanced to allow for additional
filtering of names through its SELEQ parameter. Filters have been added
to view only files, groups, accounts, directories, and symbolic links.
For example, to list all the directories under your CWD use the
MPE-escape name syntax in conjunction with the DIR or DIRECTORY filter as
in the following command:
:listfile ./@; seleq=[object=dir]
To list all uppercase directory names use the MPE name syntax as in the
following command:
:listfile @; seleq=[object=dir]
Similarly, to show all symbolic links that you may have created under
your CWD enter the following command:
:listfile ./@; seleq=[object=symlink]
The following table indicates which filter is allowed with each type of
syntax.
DIR or
| FILE DIRECTORY HFSDIR SYMLINK GROUP ACCOUNT
-------------------------------------------------------------------
MPE | yes yes yes yes no no
|
MPE-escape | yes yes yes yes yes yes
Note that MPE syntax displays all names that adhere to MPE naming
conventions, whereas MPE-escaped name syntax includes all object names.
Also, HFSDIR does not display MPE group and account names when the
pathname includes those objects. It only displays "true" HFS directory
names. Using our example directory we can enter the following command
and display only "true" HFS directory names as follows:
:listfile /; seleq=[object=hfsdir]
PATH= /
users/
Using DIRECTORY or DIR filters would result in the following:
:listfile /; seleq=[object=dir]
PATH= /
DEVELOP/ PAYROLL/ users/
LISTFILE HFS Formats Have Changed From Release 4.5.
The POSIX displays produced by the LISTFILE command have changed in
release 5.0. You do not need to read this section if you are not a user
of release 4.5. Otherwise, the changes are:
1. Removal of the extraneous "./" and "../" from the pathname in
"PATH= pathname" HFS format header
2. Addition of a blank line to the end of all formats except format
-1
3. Deletion of the blank line from the end of format -1
LISTF Supports All Formats Allowed by LISTFILE.
The LISTF command now supports all the formats that LISTFILE allows.
This means addition of formats -5, 5, and 7. Note that unlike LISTFILE,
LISTF does not accept MPE-escaped syntax and as such the addition of
these formats pertains only to objects whose names adhere to MPE naming
conventions.
List of Enhanced MPE Commands
Several old MPE commands have been enhanced to recognize MPE-escaped
syntax as well as provide new functionality. These are: ALTSEC, BUILD,
COPY, FILE (actual designator), LISTFILE, PRINT, RENAME, PURGE, RELEASE,
RESTORE, RUN, SAVE, SECURE, STORE.
Additionally, LISTF has been enhanced to accept all format numbers that
are supported by LISTFILE, but LISTF does not accept MPE-escaped syntax.
Miscellaneous Enhancements
Command Buffer Size Has Been Increased to 511 Characters.
CI's command buffer size has been increased to 511 characters from the
traditional size of 279 characters allowing for longer POSIX pathnames.
Given the same command image, a pathname can be 233 (511-279 inclusive)
characters longer in 5.0 than it would be without the increase in buffer
size.
Note that the maximum size of a pathname in a native mode (NM) command
now is 511 characters less the length of the command name and other
parameters. The maximum size of a pathname in a compatibility mode (CM)
command is 253 for relative and 255 for absolute pathnames. The CM
buffer size restriction is due to limits imposed by the MYCOMMAND
intrinsic. Also if a POSIX object is directly under the root, an
account, or an MPE group its name length is restricted to a maximum of 16
characters.
CI Error Messages Are in Mixed Case Letters.
All MPE/iX CI error message text is now generated in mixed case, rather
than only in all uppercase as in the past. This enhancement provides
more readable error messages. This change may have an effect on
third-party software that examines these messages.
Some Useful UDCs
This release of MPE/iX also contains some useful UDCs in the Fundamental
Operating System (FOS). These UDCs are provided for the convenience of
users on the system. These are not enabled by default. Here is the list
of the UDCs and a brief description of what each UDC does. The UDCs can
be found in the file HPPXUDC.PUB.SYS.
FINDDIR This UDC searches for a directory. It is an interface to
the LISTFILE command.
FINDFILE This UDC searches for a file. It is an interface to the
LISTFILE command.
LISTDIR This UDC lists all files which are directories. It is an
interface to the LISTFILE command.
PLISTF LISTF syntax that supports MPE-escaped syntax for the
fileset and listfile parameters of the LISTF command. It
is an interface to the LISTFILE command.
SH Invokes the MPE/iX Shell with the -L option. -L causes the
shell to read the environment initialization files.
Additional Information
For more information consult the MPE/iX Commands Reference Manual
(Volumes I and II) (32650-60115).