That isn't a bash ism. The set -C (aka set -o noclobber) option and its interaction with the:
Code:
fd> file
and:
Code:
fd>| file
redirection operators is required in all POSIX conforming shells...
Code:
#!/bin/bash
options=$(set +o) # Save current shell options
set -C # Set noclobber option (synonym for "set -o noclobber"
if > xyzzy # Fail if file already exists
then echo '> xyzzy succeeded'
else echo '> xyzzy failed'
fi
if > xyzzy # Fail if file already exists
then echo '2nd > xyzzy succeeded'
else echo '2nd > xyzzy failed'
fi
if >| xyzzy # Succeed even if file already exists (as long as you
# have write permission)
then echo '>| xyzzy succeeded'
else echo '>| xyzzy failed'
fi
$options # Reset original shell options
rm -f xyzzy # Remove test file
i have been interacting a little with the forum in the last couple of days and to tell the truth I have learnt quite a bit from some of the posts that I have read accessed or posted.. from some of the books that I have read I have a pretty good idea about shells, profile files, .bashrc, etc, etc... (4 Replies)
Hi,
I have one file stat.
Stat file contents are as follows: for example.
H50768020040913,00260100,507680,13,0000000643,0000000643,00000,0000
H50769520040808,00260100,507695,13,0000000000,0000000000,00000,0000 H50770620040611,00260100,507706,13,0000000000,0000000000,00000,0000
Now i... (1 Reply)
Sun Microsystems Inc. SunOS 5.9
I am hoping someone has come across this before. I have a script that transfers several gz files via Secure FTP across to an SFTP server on an NT machine.
The transfers show as successful:
pack12_200812160337.tar.gz | 768kB | 768kB/s | ETA: 00:00:01 | 37%... (5 Replies)
Hi
I've 2 folder A and B, they have files with the same name but different content.
I mean
A contain---------> aa.txt, bb.txt, cc.txt
B contain---------> aa.txt, bb.txt, cc.txt
but aa.txt in A has different content from aa.txt in B.
I'd like to parse the homonyms files in... (7 Replies)
Hey guys,
Sorry for the basic question but I have a lot of files that I want to separate into groups based on filenames which I can then cat together. Eg I have:
(a_b_c.txt)
WB34_2_SLA8.txt
WB34_1_SLA8.txt
WB34_1_DB10.txt
WB34_2_DB10.txt
WB34_1_SLA8.txt
WB34_2_SLA8.txt
77_1_SLA8.txt... (1 Reply)
Hi,
I am trying to use lftp to mirror two directories: one on my windows pc and one on a zOS system. One file within the local directory has special characters for different languages, e.g. pou¶ít (czech). When I run lftp, the characters are incorrect.
I am transferring in ASCII mode, and the... (5 Replies)
I've got a disorganized list of items and quantities for each. I've been using a combination of grep and sort to find out how much to buy of each item. I'm tired of having to constantly using these commands so I've been trying to write a shell script to make it easier, but I can't figure out how... (3 Replies)
#!/bin/bash
#
name=$1
type=$2
number=1
for file in ./**
do
if
then
filenumber=00$number
elif
then
filenumber=0$number
fi
tempname="$name""$filenumber"."$type"
if (4 Replies)
I have a bunch of files that are messages in my directory. Each message has a date located in the file. How can I look into each file and find the date?
Thank you for any help (7 Replies)
Discussion started by: totoro125
7 Replies
LEARN ABOUT SUSE
ionice
ionice(1) General Commands Manual ionice(1)NAME
ionice - get/set program io scheduling class and priority
SYNOPSIS
ionice [[-c class] [-n classdata] [-t]] -p PID [PID]...
ionice [-c class] [-n classdata] [-t] COMMAND [ARG]...
DESCRIPTION
This program sets or gets the io scheduling class and priority for a program. If no arguments or just -p is given, ionice will query the
current io scheduling class and priority for that process.
As of this writing, a process can be in one of three scheduling classes:
Idle A program running with idle io priority will only get disk time when no other program has asked for disk io for a defined grace
period. The impact of idle io processes on normal system activity should be zero. This scheduling class does not take a priority
argument. Presently, this scheduling class is permitted for an ordinary user (since kernel 2.6.25).
Best effort
This is the effective scheduling class for any process that has not asked for a specific io priority. This class takes a priority
argument from 0-7, with lower number being higher priority. Programs running at the same best effort priority are served in a round-
robin fashion.
Note that before kernel 2.6.26 a process that has not asked for an io priority formally uses "none" as scheduling class, but the io
scheduler will treat such processes as if it were in the best effort class. The priority within the best effort class will be dynam-
ically derived from the cpu nice level of the process: io_priority = (cpu_nice + 20) / 5.
For kernels after 2.6.26 with CFQ io scheduler a process that has not asked for an io priority inherits CPU scheduling class. The
io priority is derived from the cpu nice level of the process (same as before kernel 2.6.26).
Real time
The RT scheduling class is given first access to the disk, regardless of what else is going on in the system. Thus the RT class
needs to be used with some care, as it can starve other processes. As with the best effort class, 8 priority levels are defined
denoting how big a time slice a given process will receive on each scheduling window. This scheduling class is not permitted for an
ordinary (i.e., non-root) user.
OPTIONS -c class
The scheduling class. 0 for none, 1 for real time, 2 for best-effort, 3 for idle.
-n classdata
The scheduling class data. This defines the class data, if the class accepts an argument. For real time and best-effort, 0-7 is
valid data.
-p pid Pass in process PID(s) to view or change already running processes. If this argument is not given, ionice will run the listed pro-
gram with the given parameters.
-t Ignore failure to set requested priority. If COMMAND or PID(s) is specified, run it even in case it was not possible to set desired
scheduling priority, what can happen due to insufficient privilegies or old kernel version.
EXAMPLES
# ionice -c 3 -p 89
Sets process with PID 89 as an idle io process.
# ionice -c 2 -n 0 bash
Runs 'bash' as a best-effort program with highest priority.
# ionice -p 89 91
Prints the class and priority of the processes with PID 89 and 91.
NOTES
Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler.
AUTHORS
Jens Axboe <jens@axboe.dk>
AVAILABILITY
The ionice command is part of the util-linux-ng package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
ionice August 2005 ionice(1)