A prefix sequence is one or more special characters.
Type one or more prefix sequences immediately preceding the
characters of the command without any intervening blanks. If you want
to specify more than one sequence, you can type them in any order,
but characters within any multicharacter sequence must be typed in order.
If you type any prefix sequences, you must enclose the entire command,
including the prefix sequences in double quotation marks, as in the
following examples:
- On Linux and UNIX operating systems:
rah "};ps -F pid,ppid,etime,args -u $USER"
db2_all "};ps -F pid,ppid,etime,args -u $USER"
- On Windows operating
systems:
rah "||db2 get db cfg for sample"
db2_all "||db2 get db cfg for sample"
The prefix sequences are:
- Sequence
- Purpose
- |
- Runs the commands in sequence in the background.
- |&
- Runs the commands in sequence in the background and terminates
the command after all remote commands have completed, even if some
processes are still running. This might be later if, for example,
child processes (on Linux and UNIX operating systems) or background
processes (on Windows operating
systems) are still running. In this case, the command starts a separate
background process to retrieve any remote output generated after command
termination and writes it back to the originating computer.
Note: On Linux and UNIX operating systems, specifying & degrades
performance, because more rsh commands are required.
- ||
- Runs the commands in parallel in the background.
- ||&
- Runs the commands in parallel in the background and terminates
the command after all remote commands have completed as described
previously for the |& case.
Note: On Linux and UNIX operating
systems, specifying & degrades performance, because
more rsh commands are required.
- ;
- Same as ||&. This is an alternative shorter form.
Note: On Linux and UNIX operating systems, specifying ; degrades
performance relative to ||, because more rsh commands
are required.
- ]
- Prepends dot-execution of user's profile before executing command.
Note: Available
on Linux and UNIX operating systems only.
- }
- Prepends dot-execution of file named in $RAHENV (probably .kshrc)
before executing command.
Note: Available on Linux and UNIX operating
systems only.
- ]}
- Prepends dot-execution of user's profile followed by execution
of file named in $RAHENV (probably .kshrc)
before executing command.
Note: Available on Linux and UNIX operating
systems only.
- )
- Suppresses execution of user's profile and of file named in $RAHENV.
Note: Available
on Linux and UNIX operating systems only.
- '
- Echoes the command invocation to the computer.
- <
- Sends to all the computers except this one.
- <<-nnn<
Sends to all-but-database partition server nnn (all
database partition servers in db2nodes.cfg except
for database partition number nnn, see the first
paragraph following the last prefix sequence in this table).
nnn is
the corresponding 1-, 2-, or 3-digit database partition number to
the nodenum value in the db2nodes.cfg file.
<<-nnn< is
only applicable to db2_all.
- <<+nnn<
Sends to only database partition server nnn (the database partition server in db2nodes.cfg whose
database partition number is nnn, see the first
paragraph following the last prefix sequence in this table).
nnn is
the corresponding 1-, 2-, or 3-digit database partition number to
the nodenum value in the db2nodes.cfg file.
<<+nnn< is
only applicable to db2_all.
- (blank character)
- Runs the remote command in the background with stdin, stdout,
and stderr all closed. This option is valid only
when running the command in the background, that is, only in a prefix
sequence which also includes \ or ;. It allows the command to complete
much sooner (as soon as the remote command has been initiated). If
you specify this prefix sequence on the rah command
line, then either enclose the command in single quotation marks, or
enclose the command in double quotation marks, and precede the prefix
character by \ . For example,
rah '; mydaemon'
or rah ";\ mydaemon"
When run as a background
process, the rah command never waits for any output
to be returned.
- >
- Substitutes occurrences of > with the computer name.
- "
- Substitutes occurrences of () by the computer index, and substitutes
occurrences of ## by the database partition number.
- The computer index is a number that associated with a computer
in the database system. If you are not running multiple logical partitions,
the computer index for a computer corresponds to the database partition
number for that computer in the database partition configuration file. To
obtain the computer index for a computer in a multiple logical partition
database environment, do not count duplicate entries for those computers
that run multiple logical partitions. For example, if MACH1 is running
two logical partitions and MACH2 is also running two logical partitions,
the database partition number for MACH3 is 5 in the
database partition configuration file. The computer index for MACH3,
however, would be 3.
- On Windows operating
systems, do not edit the database partition configuration file. To
obtain the computer index, use the db2nlist command.
- When " is specified, duplicates are not eliminated
from the list of computers.
Usage notes
- Prefix sequences are considered to be part of the command. If
you specify a prefix sequence as part of a command, you must enclose
the entire command, including the prefix sequences, in double quotation
marks.
DB2 10.5 for Linux, UNIX, and Windows