I stumbled across a somewhat strange behavior of tar and find no explanation for it: i was testing a DVD for read errors and thought to simply tar the content and direct the output to /dev/null:
This way i expected the system to read the complete content and eventually to report a read error if there is one. To my amazement the command came back immediately without any error. Still i didn't believe it had read anything (save for maybe the directory information) so i directed the output to a real file instead.
This time tar did read the files and subsequently reported the read error i was expecting in one file.
My question is, why didn't it read the files before? Is there something i am missing?
Please help urgently.
I need to setup up some sort of service on a solaris server on a port.
I dont need it do anything special, anything that is sent to this port from an external server should be dump to /dev/null or a flat file..
Can you help urgently? (1 Reply)
Hi, Anyone can help
My solaris 8 system has the following
/dev/null , /dev/tty and /dev/console
All permission are lrwxrwxrwx
Can this be change to a non-world write ??
any impact ?? (12 Replies)
Hello,
I am working on a script to measure the read performance of a busybox environment. The logical choice is to use a command line like:
(time cp * /dev/null) 2> /tmp/howlong.txt
Ah, the rub is cp or /dev/null will only accept a single file at a time.
The result in the txt file is and... (1 Reply)
Hello,
I'm trying to send the error output of a 'cat' operation to /dev/null like this:
cat /dirA/dirB/temp*.log > /dirA/dirB/final.log 2>/dev/null
This works perfectly in a terminal, but not when placed in a script.
If there are no files matching temp*.log the script outputs an error... (7 Replies)
How are these two different? They both prevent output and error from being displayed. I don't see the use of the "&"
echo "hello" > /dev/null 2>&1
echo "hello" > /dev/null 2>1 (3 Replies)
I apologize if this question has been answered else where or is too elementary.
I ran across a KSH script (long unimportant story) that does this:
if ; then
CAS_SRC_LOG="/var/log/cas_src.log 2>&1"
else
CAS_SRC_LOG="/dev/null 2>&1"
fithen does this:
/usr/bin/echo "heartbeat:... (5 Replies)
I'm using an text-to-speech synthesis in a script, and I need to redirect it's output to /dev/null
how can I do that ? And how to redirect the stream to his normal output then (sound card ) ?
thankx (2 Replies)
Friends have the following problem
a search may not find anything which would correct example:
ls -ltr *prueba.txt | nawk '{ print $9 }' > Procesar.dat 2>/dev/null
When he finds nothing gives me the following error
ls: prueba.txt: No such file or directory
because 2> / dev / null... (4 Replies)
Discussion started by: tricampeon81
4 Replies
LEARN ABOUT SUNOS
chroot
chroot(1M) System Administration Commands chroot(1M)NAME
chroot - change root directory for a command
SYNOPSIS
/usr/sbin/chroot newroot command
DESCRIPTION
The chroot utility causes command to be executed relative to newroot. The meaning of any initial slashes (/) in the path names is changed
to newroot for command and any of its child processes. Upon execution, the initial working directory is newroot.
Notice that redirecting the output of command to a file,
chroot newroot command >x
will create the file x relative to the original root of command, not the new one.
The new root path name is always relative to the current root. Even if a chroot is currently in effect, the newroot argument is relative to
the current root of the running process.
This command can be run only by the super-user.
RETURN VALUES
The exit status of chroot is the return value of command.
EXAMPLES
Example 1: Using the chroot Utility
The chroot utility provides an easy way to extract tar files (see tar(1)) written with absolute filenames to a different location. It is
necessary to copy the shared libraries used by tar (see ldd(1)) to the newroot filesystem.
example# mkdir /tmp/lib; cd /lib
example# cp ld.so.1 libc.so.1 libcmd.so.1 libdl.so.1 libsec.so.1 /tmp/lib
example# cp /usr/bin/tar /tmp
example# dd if=/dev/rmt/0 | chroot /tmp tar xvf -
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO cd(1), tar(1), chroot(2), ttyname(3C), attributes(5)NOTES
Exercise extreme caution when referencing device files in the new root file system.
References by routines such as ttyname(3C) to stdin, stdout, and stderr will find that the device associated with the file descriptor is
unknown after chroot is run.
SunOS 5.10 15 Dec 2003 chroot(1M)