Hi,
I am new into UNIX shell scripting and I am wondering what is the meaning of the below text which appears at the end of each line in the ".sh" file:
> /dev/null 2>&1
For example, the line below:
sh $HOME/stats/Rep777/Act_777.sh omc omc > /dev/null 2>&1
I know for sure what "sh... (10 Replies)
what if the difference between
#!/bin/sh
and
#!/bin/bash
I wrote a script with the second heading now when i change my heading to the first one ...the script is not executing well....im not getting the required output....any solution to this problem...or do i have to start the... (3 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)
why is this giving me errors?
i type this in: find / -name "something.txt" 2>/dev/null
i get the following error messages:
find: bad option 2
find: path-list predicate-list
:confused: (5 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 came across and unexpected behavior with redirections in tcsh. I know, csh is not best for redirections, but I'd like to understand what is happening here.
I have following script (called out_to_streams.csh):
#!/bin/tcsh -f
echo Redirected to STDOUT > /dev/stdout
echo Redirected to... (2 Replies)
Hi all.
I have a .txt file that I need to sort it
My file is like:
1- 88 chain0 MASTER (FF-TE) FFFF 1962510 /TCK T FD2TQHVTT1 /jtagc/jtag_instreg/updateinstr_reg_1 dff1 (TI,SO)
2- ... (10 Replies)
Basically I want to shorten URLs on my html pasting site (pasteht.ml), by using "/~a1Pha" instead of "/paste/a1Pha". The ID is 5 numbers and letters, both cases.
For example:
/~idnum serves /paste/idnum.htm
/=idnum serves /paste/idnum.htm
/paste/idnum redirects to /~idnum (to update any old... (0 Replies)
I am trying find files in sub dir with certain tags using tag command, and add the period to the beginning. I can't use chflags hidden {} cause it doesn't add period to the beginning of the string for web purpose. So far with my knowledge, I only know mdfind or tag can be used to search files with... (6 Replies)
Discussion started by: Nexeu
6 Replies
LEARN ABOUT REDHAT
pivot_root
PIVOT_ROOT(8) Maintenance Commands PIVOT_ROOT(8)NAME
pivot_root - change the root file system
SYNOPSIS
pivot_root new_root put_old
DESCRIPTION
pivot_root moves the root file system of the current process to the directory put_old and makes new_root the new root file system. Since
pivot_root(8) simply calls pivot_root(2), we refer to the man page of the latter for further details.
Note that, depending on the implementation of pivot_root, root and cwd of the caller may or may not change. The following is a sequence for
invoking pivot_root that works in either case, assuming that pivot_root and chroot are in the current PATH:
cd new_root
pivot_root . put_old
exec chroot . command
Note that chroot must be available under the old root and under the new root, because pivot_root may or may not have implicitly changed the
root directory of the shell.
Note that exec chroot changes the running executable, which is necessary if the old root directory should be unmounted afterwards. Also
note that standard input, output, and error may still point to a device on the old root file system, keeping it busy. They can easily be
changed when invoking chroot (see below; note the absence of leading slashes to make it work whether pivot_root has changed the shell's
root or not).
EXAMPLES
Change the root file system to /dev/hda1 from an interactive shell:
mount /dev/hda1 /new-root
cd /new-root
pivot_root . old-root
exec chroot . sh <dev/console >dev/console 2>&1
umount /old-root
Mount the new root file system over NFS from 10.0.0.1:/my_root and run init:
ifconfig lo 127.0.0.1 up # for portmap
# configure Ethernet or such
portmap # for lockd (implicitly started by mount)
mount -o ro 10.0.0.1:/my_root /mnt
killall portmap # portmap keeps old root busy
cd /mnt
pivot_root . old_root
exec chroot . sh -c 'umount /old_root; exec /sbin/init'
<dev/console >dev/console 2>&1
SEE ALSO chroot(1), mount(8), pivot_root(2), umount(8)Linux Feb 23, 2000 PIVOT_ROOT(8)