2 i/o redirection alternatives – HP XC System 2.x Software User Manual
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commands let you choose from among any of five I/O redirection alternatives (modes) that
are explained in the next section.
-o mode
(
--output=mode
)
The
-o
option redirects standard output
stdout
for this job to mode, one of five alternative
ways to display, capture, or subdivide the job’s I/O, explained in the next section. By default,
srun
collects
stdout
from all job tasks and line buffers it to the attached terminal.
-i mode
(
--input=mode
)
The
-i
option redirects standard input
stdin
for this job from mode, one of five alternative
ways to display, capture, or subdivide the job’s I/O, explained in the next section. By default,
srun
redirects
stdin
from the attached terminal to all job tasks.
-e mode
(
--error=mode
)
The
-e
option redirects standard error
stderr
for this job to mode, one of five alternative
ways to display, capture, or subdivide the job’s I/O, explained in the next section. By default,
srun
collects
stderr
from all job tasks and line buffers it to the attached terminal, just
as with
stdout
. But you can request that
srun
handle standard output and standard error
differently by invoking
-e
and
-o
with different redirection modes.
-l
(
--label
)
The
-l
option prepends the remote task ID number to each line of standard output and standard
error. By default,
srun
line buffers this I/O to the terminal (or to specified files) without any
task labels. Options
-l
and
-u
are mutually exclusive.
-u
(
--unbuffered
)
The
-u
option prevents line buffering of standard output from remote tasks (buffering is the
srun
default). Options
-l
and
-u
are mutually exclusive.
6.4.6.2 I/O Redirection Alternatives
The
srun
I/O options
-i
(
-input
),
-o
(
-output
), and
-e
(
-error
), all take any of five
I/O redirection alternatives (modes) as arguments. These arguments are explained in this section.
all
The all argument redirects
stdout
and
stderr
from all job tasks to
srun
(and hence to the
attached terminal), and broadcasts
stdin
from
srun
(the terminal) to all remote tasks. This is
srun
’s default behavior for handling I/O.
none
The none argument redirects
stdout
and
stderr
from all job tasks to
/dev/null
(receives
no I/O from any task) and sends no
stdin
to any task (closes
stdin
).
taskid
The taskid argument redirects to
srun
(and hence to the attached terminal)
stdout
and
stderr
from the single specified task whose relative ID is taskid, where the range for integer
taskid starts at 0 (the first task) and runs through the total number of tasks in the current job
step. This choice also redirects
stdin
from
srun
(the terminal) to this single specified task.
filename
The filename argument redirects
stdout
or
stderr
from all job tasks into a single file called
filename, or broadcasts
stdin
from that same file to all remote tasks, depending upon the
I/O command.
Using SLURM
6-9