Another couple of notes about the use of a temporary file.
First off, if you will never use the first few lines of the temp file, might as well throw them away already at the start.
Secondly, when you are done, you should remove your temporary file. Better yet, remove it even if you are interrupted.
Put those lines near the beginning of the script.
Properly speaking, you should probably use something like mktemp to generate a unique, unpredictable temporary file name. There are security issues with using predictable names, and having a static file name means you can't run two instances of the script at the same time.
Hi All,
I have a pair of sun ultra 5_10 with SunOS 5.5.1.
Both are almost equally patched and set up with simillar applications.
host# uname -a
SunOS host 5.5.1 Generic_103640-24 sun4u sparc SUNW,Ultra-5_10
Even though both have
same amount of RAM ( 512 Mb ) ,
... (1 Reply)
Hi All,
Kindly help me in optimizing the server as it displays a great amount of CPU & MEM being utilised when the mysql process executes.
Below are the stats ---
--------------------------------------------------------------------------
# top
15:51:57 up 23:22, 5 users, load average:... (1 Reply)
What is amount of free RAM i have now?
total used free shared buffers cached
Mem: 1010 963 46 0 215 256
-/+ buffers/cache: 491 518
Swap: 1983 0 1983
Above is the output of... (1 Reply)
how can I find cpu usage memory usage swap usage and
I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times
my final destination is monitor process
logical volume usage above X % and number of Logical voluage above
can I not to... (3 Replies)
I'm writing a bash script to log some selections from a sensors output (core temp, mb temp, etc.) and I would also like to have the current cpu usage as a percentage. I have no idea how to go about getting it in a form that a bash script can use. For example, I would simply look in the output of... (3 Replies)
Hi all,
Is it possible to get total memory usage and free memory usage without top? By Googling I found for total memory usage, use vmstat, for CPU, use mpstat, for disk I/O use iostat, is this correct? Will using sar gives the same result as ALL of these three (3) commands?
What about if I... (2 Replies)
Hi folks,
I'm a CS students enrolled in a sysadmin class where we've been covering bash scripting for the past few weeks. I have prior knowledge in java, c++, c#, python,and some scripting languages like asp.net w/c# and php. This bash stuff seems pretty neat and a bit different than what I am... (9 Replies)
I do not know shell scripting. But at work place, I have got an in and out shell scripting task. I just need to understand a very big script. Is there any tool in which I can place the script and it can tell me the meaning of the whole script? (3 Replies)
Discussion started by: lg123
3 Replies
LEARN ABOUT REDHAT
mktemp
MKTEMP(1) BSD General Commands Manual MKTEMP(1)NAME
mktemp -- make temporary file name (unique)
SYNOPSIS
mktemp [-d] [-q] [-u] template
DESCRIPTION
The mktemp utility takes the given file name template and overwrites a portion of it to create a file name. This file name is unique and
suitable for use by the application. The template may be any file name with at least 6 of 'Xs' appended to it, for example /tmp/temp.XXXXXX.
The trailing 'Xs' are replaced with the current process number and/or a unique letter combination. The number of unique file names mktemp
can return depends on the number of 'Xs' provided; six 'Xs' will result in mktemp testing roughly 26 ** 6 combinations.
If mktemp can successfully generate a unique file name, the file is created with mode 0600 (unless the -u flag is given) and the filename is
printed to standard output.
OPTIONS
The available options are as follows:
-d Make a directory instead of a file.
-q Fail silently if an error occurs. This is useful if a script does not want error output to go to standard error.
-u Operate in ``unsafe'' mode. The temp file will be unlinked before mktemp exits. This is slightly better than mktemp(3) but still
introduces a race condition. Use of this option is not encouraged.
RETURN VALUES
The mktemp utility exits with a value of 0 on success, and 1 on failure.
EXAMPLES
The following sh(1) fragment illustrates a simple use of mktemp where the script should quit if it cannot get a safe temporary file.
TMPFILE=`mktemp /tmp/$0.XXXXXX` || exit 1
echo "program output" >> $TMPFILE
In this case, we want the script to catch the error itself.
TMPFILE=`mktemp -q /tmp/$0.XXXXXX`
if [ $? -ne 0 ]; then
echo "$0: Can't create temp file, exiting..."
exit 1
fi
Note that one can also check to see that $TMPFILE is zero length instead of checking $?. This would allow the check to be done later one in
the script (since $? would get clobbered by the next shell command).
SEE ALSO mkstemp(3), mktemp(3)HISTORY
The mktemp utility appeared in OpenBSD.
BSD November, 20, 1996 BSD