General :: Better To Use 'at' Command Instead Of Time Variable In Shutdown?
Apr 20, 2010
I was reading that if I want to do a one time scheduled command, I should use at, which I've never done, as opposed to cron, which i'm kinda familiar with. But what I want to do is reboot my server at 3am tomorrow and force it to check the file systems with a shutdown -rF. For this do I even need to use "at" or could I just say shutdown -rF 3:00.Will that also know that I mean 3am tomorrow and not say in 3 minutes from now or 3pm?
I would like to put a variable in the $PS1 prompt that will change each time a command is run. I want the color of the $PS1 prompt to change each time a command is run.I know that I can do this:
Code: PS1="h@w # " ## "#" is changes every time a command is run
In my script, I need to get execution time of a command (say 'ls') in mili seconds level. For this i tried using "time" command to retrieve the total execution time in milli seconds. But, the problem is that, how to save the output of time command in a variable. The format of the command is like "time ls -R /opt" Going further, the o/p of 'time' command is:
real 0m0.003s user 0m0.004s sys 0m0.000s
Here, in my script, I would like to use only middle line "user 0m0.004s" saved to the variable but unable to find out the way.
Im having a bit of a problem with a init script which I wrote to start and stop oracle listener and database. My system is Redhat 5.4 64bit and oracle 10g2 standard database (64). I have created the script and added the script using
chkconfig add orashut, and on the script by chkconfig level 345 orashut on Now I can use service orashut start, stop, restart, and works fine and when the system comes up the database and the listener would come up as planed. But the problem is when I do a reboot or shut down the db or the listener would not shutdown as expected, I placed at K00 values as well in rc0.d and rc6.d to give the priority at the shutdown. Even though all the configurations say this script should run before everything else at the shutdown time this is not working.
i have installed ubuntu ultimate edition 10.04 in my toshiba c650 recently,however it is taking too long before it startup. 2 when i log off the cursor still remain untill all power have been discharged. what could be the problem
I tried using the tail command in my shell script and storing that value in a variable a but an error keeps coming. Is there any other way to store the output of a command into a variable. Cannot Read text from text file and store it in a variable using shell script. The thing is I need a number from the file new.txt and use that number in my script
#!/bin/bash a = `tail -1 new.txt|head -n 1` echo $a
When I run this command from shell, it runs ok export REVS=`svn info svn+ssh://svn.myone.ca/var/svn/story/trunk/lib |grep 'Last Changed Rev:'| awk -F: '{print $2}'` However when I save it into a file called test.sh (of course, I chmod it with +x), I got error "export: 2: bad variable name"
Here is the file: #!/bin/bash export REVS=`svn info svn+ssh://svn.myone.ca/var/svn/story/trunk/lib |grep 'Last Changed Rev:'| awk -F: '{print $2}'` I am using ubuntu.
!<number> to execute the Nth command(use history to see the list). Or you can use
Code:
cd !-2:1
to cd into the value in the first field that was executed 2 commands ago Anyhow, say I run a command and the output is a path. Any way to cd and then some variable where OUTPUT of the previous command was stored? A variable that always stores the OUTPUT of the last command.
I am using CentOS5.5 & everytime it is showing command not found. If I export the path as below it will be working fine until a reboot. Again same error i.e command not found if I open new terminal. Every time I am exporting as below:
How can I set these permanently as that the paths should automatically be exported for everyone user whenever the system boots. And command completion also should happen for eg. #fdi (press tab), then it should show available options such as fdisk, etc.
I want to use PROMPT_COMMAND variable to build a history of all the commands i execute. So Basically i want to append the last executed command to my own command log file. How can i find the last executed command ?
I want to add PROMPT_COMMAND="echo $last_executed_command >> my_command_log" But I am not sure how to find the last executed command
looking for a command that shutdown/reboot my ubuntu just same as process that happened when I press shutdown buttonIn fact I need to close all programs that are running and then PC shutdown (that happened when I press shutdown button).
I have a custom command I've made to quickly shut down all of my xen instances.
Code:
[root@LCENT02 ~]# virtdown -bash: syntax error near unexpected token `2'
As you can see it fails when I try to run it on the command line. It is stored in an ~/.env file in my home directory. What is odd to me is if I open the .env file and copy the command from there and paste it into the command line, it does actually work!
Code:
[root@LCENT02 ~]# for i in `virsh list | grep -v -e Id -e --- -e Domain-0 | awk '{print $1}'`; do virsh shutdown $i; done Domain 1 is being shutdown Domain 2 is being shutdown Domain 3 is being shutdown
And this is how I have the command entered into my .env file:
Code:
alias virtdown="for i in `virsh list | grep -v -e Id -e --- -e Domain-0 | awk '{print $1}'`; do virsh shutdown $i; done
Why would this command work if you paste it onto the command line but not use the custom command virtdown?
I shutdown around 4 - 5 hours ago which would be around 14:00 to 15:00 time range. But as you can see there's no entry for it. Why? and how can i find when i last shutdown?
Code: last lyle pts/1 :0.0 Tue Jul 6 19:18 still logged in lyle :0 Tue Jul 6 19:15 still logged in lyle tty7 :0 Tue Jul 6 19:15 still logged in
Ive been using linux for a while but I am just getting into shell scripting, im currently trying to get a simple script for finding and copying files powered by the command:
Code:
This works fine from the command line but when put in a script such as:
Code:
Code:
with the keyboard inputs for $fc1 and $fc2 being *.doc and ~/test respectivly. The only problem i can see is the xargs -ivar "var" part possibly needing $var to be defined?
I've used the following script here: [URL] to upgrade Alsa to 1.0.21 in Ubuntu 8.04. Now whenever I run:
Code:
sudo shutdown -h <time> or sudo reboot from the terminal I get a rather annoying beep sound. What's even more annoying is if I use the shutdown command to specify a time I get a beep every 10 minutes or so. I've tried disabling the terminal beep in the terminal profile, disabling the beep in System/Preferences/Sound, adding "blacklist pcspkr" to /etc/modprobe.d/blacklist, and running gconf-editor from the terminal and setting /desktop/gnome/peripherals/keyboard/bell_mode to 'off' rather than 'on'.
When i use the shutdown-command in the terminal as root, it nearly works. It starts to shut down, and it looks like all programs and the kernels shuts down. I end up with a black screen, sometimes with the ubuntu-logo on, but it never powers off. I have to force it off by holding the power button. When i use the graphical interface to shut it down, it works perfectly. The poweroff-command works without problem too.
I'm timing how long it takes to run a command foo. I'm looking to append the results from the time command to a file, and discard the results from the foo command. I tried the following, but it didn't do what I want:
$ time ./foo > /dev/null >> output_from_time_command.txt
I am trying to use the time command to measure the execution time of a small program. The problem is that the command has three outputs. They look like this:
Code: $ time ./a.out real0m51.935s user0m51.060s sys0m0.040s
Should the execution time be the sum of the user and the sys time? sys time is really small.
I want to know how to set time format (12 hrs or 24 hrs) using command.I tried thisode:date +%T -s "2011-02-23 14:00"But it only displays 24 hrs format on TERMINAL but it does not SET 24 hrs format on the system
I am supposed to create an environment variable with the PRINTER variable, which should resolve to the word sales. Would the command be like this?: env PRINTER - NAME=SALES (is this the command to create that variable with resolving the word sales to it?)
My purpose is to have a different history file for each directory. Because, it would be usefull for me to access only to commands executed in each directory. In this context, is there any way to update the HISTFILE variable every time I go in a directory?
I am running a script with nohup and this generates a lot of logs.
In order to view the log I use tail -f nohup.out
The problem is that the info supplied by this command is not always the latest//sometimes I need to use the command again order to view the latest info added to the nohup.out file.
I would appreciate help with how to extract the date and time from at command jobs. From what I can tell, the date and time is embedded in the file name (/var/spool/atjobs).I'd be using this information in a (bash) shell script.
I use the time command to measure the wall-clock time of a GPU implementation of an algorithm. When I time the CPU execution of the algorithm time returns a negligible sys time. However, when I time the GPU execution time returns a sys time that is around 20-30% of the total time. If that time was comparable with the negligible sys time of the CPU I would achieve a speedup of a few times higher.
I suspect that the increased sys time is because of the GPU usage, which, I assume, takes some time for the OS because of the drivers etc. I am not sure though, and it is important to figure this out because it will improve my results a lot if I can ignore the sys time and use just the user time for speedup calculations. Also, is there a way to see, in detail, what is the sys running and takes so much time. I am thinking that I might be able to see if it is the driver indeed that causes this delay.
