GNU bash, version 4.2.8(1)-release (i686-pc-linux-gnu)
As I told in my first post for i in {1..10} works.
It should be possible to use variable in for loops too.
You can use variables in for loops, but not inside of a {}. Someone else can probably do a better job of explaining this, but the bottom line is it has to do with the order in which the shell interprets what you're putting into it. As I recall (and to be honest, I usually just learn how things work, not why, so you should probably look this up...) the reason is that expanding the {} is the very first thing the shell does, BEFORE it translates the variable into it's value. So, if you're trying to do:
(
What the shell is actually doing is for i in the literal expression {1..$x} because $x doesn't mean anything yet.
Sorry for such a dreadful title, but I'm not sure how to be more descriptive. I'm hoping some of the more gurutastic out there can take a look at a solution I came up with to a problem, and advice if there are better ways to have gone about it.
To make a long story short around 20K pieces of... (2 Replies)
I'm trying to understand if it's possible to create a set of variables that are numbered based on another variable (using eval) in a loop, and then call on it before the loop ends.
As an example I've written a script called question (The fist command is to show what is the contents of the... (2 Replies)
Hi Im running this script, which is supposed to find the max value build some tables and then stop running once all the tables are built. Thing is , it keeps assigning a null value to $h and then $g is null so it keep building tables i.e. testupdateNUL. How can I stop this? Here is what I have:
... (4 Replies)
Hi all
Sorry for the basic question, but i am writing a shell script to get around a slightly flaky binary that ships with one of our servers. This particular utility randomly generates the correct information and could work first time or may work on the 12th or 100th attempt etc !.... (4 Replies)
Hi,
hope I am posting in the right section.
My problem is that I have 2 or more arguments passed and I want to check if the arguments passed exists or not.
The first argument should not exist and the remaining others should exist.
example:
./shells.sh argument1 argument2 argument3
... (5 Replies)
Hi, I was debating if I should put this in the dummies or scripts section, I apologize in advance if I chose poorly.
Fairly new to Unix and BASH scripting but I thought I made it fairly well given my limited understanding. However, the output indicates that it's looping and I'm ending up with a... (5 Replies)
Hello All,
Maybe I'm Missing something here but I have NOOO idea what the heck is going on with this....?
I have a Variable that contains a PATTERN of what I'm considering "Illegal Characters". So what I'm doing is looping
through a string containing some of these "Illegal Characters". Now... (5 Replies)
Hi,
I want to read file multiple times. Right now i am using while loop but that is not working.
ex.
While read line
do
while read line2
do
echo stmt1
#processing some data based on data.,
done < file2.txt
done < file1.txt # This will have 10... (4 Replies)
Hi all,
i developed a script to measure the uptime of a process in a Solaris 10/11 environments.
All is well, but i came across a situation where there are multiple processes of the same name. Basically i have the following result file:
beVWARS 13357 19592122
beVWARS 14329 19591910... (4 Replies)
Discussion started by: nms
4 Replies
LEARN ABOUT XFREE86
pivot_root
PIVOT_ROOT(8) System Administration PIVOT_ROOT(8)NAME
pivot_root - change the root filesystem
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).
OPTIONS -V, --version
Display version information and exit.
-h, --help
Display help text and exit.
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), pivot_root(2), mount(8), switch_root(8), umount(8)AVAILABILITY
The pivot_root command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.
util-linux August 2011 PIVOT_ROOT(8)