Posts Tagged ‘real time’

Procedure Instructions to safe upgrade CentOS / RHEL Linux 7 Core to latest release

Thursday, February 13th, 2020

safe-upgrade-CentOS-and_Redhat_Enterprise_Linux_RHEL-7-to-latest-stable-release

Generally upgrading both RHEL and CentOS can be done straight with yum tool just we're pretty aware and mostly anyone could do the update, but it is good idea to do some
steps in advance to make backup of any old basic files that might help us to debug what is wrong in case if the Operating System fails to boot after the routine Machine OS restart
after the upgrade that is usually a good idea to make sure that machine is still bootable after the upgrade.

This procedure can be shortened or maybe extended depending on the needs of the custom case but the general framework should be useful anyways to someone that's why
I decided to post this.

Before you go lets prepare a small status script which we'll use to report status of  sysctl installed and enabled services as well as the netstat connections state and
configured IP addresses and routing on the system.

The script show_running_services_netstat_ips_route.sh to be used during our different upgrade stages:
 

# script status ###
echo "STARTED: $(date '+%Y-%m-%d_%H-%M-%S'):" | tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
systemctl list-unit-files –type=service | grep enabled
systemctl | grep ".service" | grep "running"
netstat -tulpn
netstat -r
ip a s
/sbin/route -n
echo "ENDED $(date '+%Y-%m-%d_%H-%M-%S'):" | tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
####

 

– Save the script in any file like /root/status.sh

– Make the /root/logs directoriy.
 

[root@redhat: ~ ]# mkdir /root/logs
[root@redhat: ~ ]# vim /root/status.sh
[root@redhat: ~ ]# chmod +x /root/status.sh

 

1. Get a dump of CentOS installed version release and grub-mkconfig generated os_probe

 

[root@redhat: ~ ]# cat /etc/redhat-release  > /root/logs/redhat-release-vorher-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out
[root@redhat: ~ ]# cat /etc/grub.d/30_os-prober > /root/logs/grub2-efi-vorher-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

2. Clear old versionlock marked RPM packages (if there are such)

 

On servers maintained by multitude of system administrators just like the case is inside a Global Corporations and generally in the corporate world , where people do access the systems via LDAP and more than a single person
has superuser privileges. It is a good prevention measure to use yum package management  functionality to RPM based Linux distributions called  versionlock.
versionlock for those who hear it for a first time is locking the versions of the installed RPM packages so if someone by mistake or on purpose decides to do something like :

[root@redhat: ~ ]# yum install packageversion

Having the versionlock set will prevent the updated package to be installed with a different branch package version.

Also it will prevent a playful unknowing person who just wants to upgrade the system without any deep knowledge to be able to
run

[root@redhat: ~ ]# yum upgrade

update and leave the system in unbootable state, that will be only revealed during the next system reboot.

If you haven't used versionlock before and you want to use it you can do it with:

[root@redhat: ~ ]# yum install yum-plugin-versionlock

To add all the packages for compiling C code and all the interdependend packages, you can do something like:

 

[root@redhat: ~ ]# yum versionlock gcc-*

If you want to clear up the versionlock, once it is in use run:

[root@redhat: ~ ]#  yum versionlock clear
[root@redhat: ~ ]#  yum versionlock list

 

3.  Check RPC enabled / disabled

 

This step is not necessery but it is a good idea to check whether it running on the system, because sometimes after upgrade rpcbind gets automatically started after package upgrade and reboot. 
If we find it running we'll need to stop and mask the service.

 

# check if rpc enabled
[root@redhat: ~ ]# systemctl list-unit-files|grep -i rpc
var-lib-nfs-rpc_pipefs.mount                                      static
auth-rpcgss-module.service                                        static
rpc-gssd.service                                                  static
rpc-rquotad.service                                               disabled
rpc-statd-notify.service                                          static
rpc-statd.service                                                 static
rpcbind.service                                                   disabled
rpcgssd.service                                                   static
rpcidmapd.service                                                 static
rpcbind.socket                                                    disabled
rpc_pipefs.target                                                 static
rpcbind.target                                                    static

[root@redhat: ~ ]# systemctl status rpcbind.service
● rpcbind.service – RPC bind service
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.service; disabled; vendor preset: enabled)
   Active: inactive (dead)

 

[root@redhat: ~ ]# systemctl status rpcbind.socket
● rpcbind.socket – RPCbind Server Activation Socket
   Loaded: loaded (/usr/lib/systemd/system/rpcbind.socket; disabled; vendor preset: enabled)
   Active: inactive (dead)
   Listen: /var/run/rpcbind.sock (Stream)
           0.0.0.0:111 (Stream)
           0.0.0.0:111 (Datagram)
           [::]:111 (Stream)
           [::]:111 (Datagram)

 

4. Check any previously existing downloaded / installed RPMs (check yum cache)

 

yum install package-name / yum upgrade keeps downloaded packages via its operations inside its cache directory structures in /var/cache/yum/*.
Hence it is good idea to check what were the previously installed packages and their count.

 

[root@redhat: ~ ]# cd /var/cache/yum/x86_64/;
[root@redhat: ~ ]# find . -iname '*.rpm'|wc -l

 

5. List RPM repositories set on the server

 

 [root@redhat: ~ ]# yum repolist
Loaded plugins: fastestmirror, versionlock
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
Determining fastest mirrors
repo id                                                                                 repo name                                                                                                            status
!atos-ac/7/x86_64                                                                       Atos Repository                                                                                                       3,128
!base/7/x86_64                                                                          CentOS-7 – Base                                                                                                      10,019
!cr/7/x86_64                                                                            CentOS-7 – CR                                                                                                         2,686
!epel/x86_64                                                                            Extra Packages for Enterprise Linux 7 – x86_64                                                                          165
!extras/7/x86_64                                                                        CentOS-7 – Extras                                                                                                       435
!updates/7/x86_64                                                                       CentOS-7 – Updates                                                                                                    2,500

 

This step is mandatory to make sure you're upgrading to latest packages from the right repositories for more concretics check what is inside in confs /etc/yum.repos.d/ ,  /etc/yum.conf 
 

6. Clean up any old rpm yum cache packages

 

This step is again mandatory but a good to follow just to have some more clearness on what packages is our upgrade downloading (not to mix up the old upgrades / installs with our newest one).
For documentation purposes all deleted packages list if such is to be kept under /root/logs/yumclean-install*.out file

[root@redhat: ~ ]# yum clean all |tee /root/logs/yumcleanall-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

7. List the upgradeable packages's latest repository provided versions

 

[root@redhat: ~ ]# yum check-update |tee /root/logs/yumcheckupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

Then to be aware how many packages we'll be updating:

 

[root@redhat: ~ ]#  yum check-update | wc -l

 

8. Apply the actual uplisted RPM packages to be upgraded

 

[root@redhat: ~ ]# yum update |tee /root/logs/yumupdate-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

Again output is logged to /root/logs/yumcheckupate-*.out 

 

9. Monitor downloaded packages count real time

 

To make sure yum upgrade is not in some hanging state and just get some general idea in which state of the upgrade is it e.g. Download / Pre-Update / Install  / Upgrade/ Post-Update etc.
in mean time when yum upgrade is running to monitor,  how many packages has the yum upgrade downloaded from remote RPM set repositories:

 

[root@redhat: ~ ]#  watch "ls -al /var/cache/yum/x86_64/7Server/…OS-repository…/packages/|wc -l"

 

10. Run status script to get the status again

 

[root@redhat: ~ ]# sh /root/status.sh |tee /root/logs/status-before-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

11. Add back versionlock for all RPM packs

 

Set all RPM packages installed on the RHEL / CentOS versionlock for all packages.

 

#==if needed
# yum versionlock \*

 

 

12. Get whether old software configuration is not messed up during the Package upgrade (Lookup the logs for .rpmsave and .rpmnew)

 

During the upgrade old RPM configuration is probably changed and yum did automatically save .rpmsave / .rpmnew saves of it thus it is a good idea to grep the prepared logs for any matches of this 2 strings :
 

[root@redhat: ~ ]#   grep -i ".rpm" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out
[root@redhat: ~ ]#  grep -i ".rpmsave" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out
[root@redhat: ~ ]#  grep -i ".rpmnew" /root/logs/yumupdate-server-host-2020-01-20_14-30-41.out


If above commands returns output usually it is fine if there is is .rpmnew output but, if you get grep output of .rpmsave it is a good idea to review the files compare with the original files that were .rpmsaved with the 
substituted config file and atune the differences with the changes manually made for some program functionality.

What are the .rpmsave / .rpmnew files ?
This files are coded files that got triggered by the RPM install / upgrade due to prewritten procedures on time of RPM build.

 

If a file was installed as part of a rpm, it is a config file (i.e. marked with the %config tag), you've edited the file afterwards and you now update the rpm then the new config file (from the newer rpm) will replace your old config file (i.e. become the active file).
The latter will be renamed with the .rpmsave suffix.

If a file was installed as part of a rpm, it is a noreplace-config file (i.e. marked with the %config(noreplace) tag), you've edited the file afterwards and you now update the rpm then your old config file will stay in place (i.e. stay active) and the new config file (from the newer rpm) will be copied to disk with the .rpmnew suffix.
See e.g. this table for all the details. 

In both cases you or some program has edited the config file(s) and that's why you see the .rpmsave / .rpmnew files after the upgrade because rpm will upgrade config files silently and without backup files if the local file is untouched.

After a system upgrade it is a good idea to scan your filesystem for these files and make sure that correct config files are active and maybe merge the new contents from the .rpmnew files into the production files. You can remove the .rpmsave and .rpmnew files when you're done.


If you need to get a list of all .rpmnew .rpmsave files on the server do:

[root@redhat: ~ ]#  find / -print | egrep "rpmnew$|rpmsave$

 

13. Reboot the system 

To check whether on next hang up or power outage the system will boot normally after the upgrade, reboot to test it.

 

you can :

 

[root@redhat: ~ ]#  reboot

 

either

[root@redhat: ~ ]#  shutdown -r now


or if on newer Linux with systemd in ues below systemctl reboot.target.

[root@redhat: ~ ]#  systemctl start reboot.target

 

14. Get again the system status with our status script after reboot

[root@redhat: ~ ]#  sh /root/status.sh |tee /root/logs/status-after-$(hostname)-$(date '+%Y-%m-%d_%H-%M-%S').out

 

15. Clean up any versionlocks if earlier set

 

[root@redhat: ~ ]# yum versionlock clear
[root@redhat: ~ ]# yum versionlock list

 

16. Check services and logs for problems

 

After the reboot Check closely all running services on system make sure every process / listening ports and services on the system are running fine, just like before the upgrade.
If the sytem had firewall,  check whether firewall rules are not broken, e.g. some NAT is not missing or anything earlier configured to automatically start via /etc/rc.local or some other
custom scripts were run and have done what was expected. 
Go through all the logs in /var/log that are most essential /var/log/boot.log , /var/log/messages … yum.log etc. that could reveal any issues after the boot. In case if running some application server or mail server check /var/log/mail.log or whenever it is configured to log.
If the system runs apache closely check the logs /var/log/httpd/error.log or php_errors.log for any strange errors that occured due to some issues caused by the newer installed packages.
Usually most of the cases all this should be flawless but a multiple check over your work is a stake for good results.
 

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Posted in Linux, System Administration, Various | No Comments »

Linux watch Windows equivalent command bat script – How to Run a command every XXX seconds on Windows

Tuesday, May 27th, 2014

windows-watch-command-linux-watch-windows-equivalent-run-script-every-xxx-seconds-on-microsoft-windows
If you're a Linux administrator you're probably already quite used to watch command which allows to execute a program periodically, showing output fullscreen. Watch is very useful to run a specific command every XXX seconds, and see the results constantly updated. watch is very useful to keep an eye on growing files, i.e.: lets say keep an eye on SQL dump:

watch "ls -al some-dump-file.sql"

or keep an eye on how a directory keeps growing in real time

watch -n 5 "du -hsc /tmp"


Above command would tell watch to refresh du -hsc /tmp on a 5 seconds interval.

So a logical question pops up "Is there a command line equivalent to Linux's watch?" In Windows there is no native command equivalent of Linux watch but there is one liner bat (Batch) script to equivalent to emulate Linux watch in Windows. The Watch like script in Windows OS looks like so:

@ECHO OFF
:loop
tasklist timeout /t 2
goto loop


Use notepad and paste above batch script to any file and save it as whateverfile.bat, running it will make all processes to get listed occuring every 2 seconds (/t 2 – is an argumeent telling the loop to expire on every 2 seconds).

Modify the script to monitor whatever Windows command you like 🙂
Enjoy

 

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Posted in Everyday Life, Programming, System Administration, Various, Windows | No Comments »

Convert WAV to MP3 in command line with LAME on Linux

Friday, April 8th, 2011

I needed to convert a bunch of files from WAV to MP3 format on my Linux desktop.

I’ve placed all my wav files to the directory /home/hipo/wav

And then I issued the small one liner script to convert the .wav files to .mp3 using the niftly lame linux mp3 convertor.

Here is how I did it:

linux-desktop:~$ cd wav
linux-desktop:/home/hipo/wav$ for i in *.wav; do
new_name=$(echo $i |sed -e 's#wav#mp3#g');
lame -V0 -h -b 160 --vbr-new "$i" "$new_name";
done

After executing the little script you might go and have a coffee, if you have thousands of files, each file convertion takes about 10-15 seconds of time (speed depends on your CPU).

Here is some output from a lame convertion to mp3 taking place:

Encoding as 8 kHz single-ch MPEG-2.5 Layer III VBR(q=0)
Frame | CPU time/estim | REAL time/estim | play/CPU | ETA
27237/27237 (100%)| 0:12/ 0:12| 0:12/ 0:12| 155.89x| 0:00
64 [27237] ***************************************************************
----------------------------------------------
kbps mono % long switch short %
64.0 100.0 84.1 8.9 7.0 If you want to save my convertion quickly for a later, download my Convert WAV to mp3 from a directory with lame shell script here

Actually there are plenty of other ways to convert wav to mp3 on Linux through mplayer, ffmpeg even with mpg123.

There are also some GUI programs that could do the convertion like winff , however for some weird reason after installing WinFF on my debian it was not able to complete convertion to mp3?!
But it doesn’t matter, the good news is I did what I wanted to via the simple lame program and the above script, hope it helps somebody out there.

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Posted in Linux and FreeBSD Desktop, Linux Audio & Video | 8 Comments »

How to delete million of files on busy Linux servers (Work out Argument list too long)

Tuesday, March 20th, 2012

How to Delete million or many thousands of files in the same directory on GNU / Linux and FreeBSD

If you try to delete more than 131072 of files on Linux with rm -f *, where the files are all stored in the same directory, you will get an error:

/bin/rm: Argument list too long.

I've earlier blogged on deleting multiple files on Linux and FreeBSD and this is not my first time facing this error.
Anyways, as time passed, I've found few other new ways to delete large multitudes of files from a server.

In this article, I will explain shortly few approaches to delete few million of obsolete files to clean some space on your server.
Here are 3 methods to use to clean your tons of junk files.

1. Using Linux find command to wipe out millions of files

a.) Finding and deleting files using find's -exec switch:

# find . -type f -exec rm -fv {} \;

This method works fine but it has 1 downside, file deletion is too slow as for each found file external rm command is invoked.

For half a million of files or more, using this method will take "long". However from a server hard disk stressing point of view it is not so bad as, the files deletion is not putting too much strain on the server hard disk.
b.) Finding and deleting big number of files with find's -delete argument:

Luckily, there is a better way to delete the files, by using find's command embedded -delete argument:

# find . -type f -print -delete

c.) Deleting and printing out deleted files with find's -print arg

If you would like to output on your terminal, what files find is deleting in "real time" add -print:

# find . -type f -print -delete

To prevent your server hard disk from being stressed and hence save your self from server normal operation "outages", it is good to combine find command with ionice, e.g.:

# ionice -c 3 find . -type f -print -delete

Just note, that ionice cannot guarantee find's opeartions will not affect severely hard disk i/o requests. On  heavily busy servers with high amounts of disk i/o writes still applying the ionice will not prevent the server from being hanged! Be sure to always keep an eye on the server, while deleting the files nomatter with or without ionice. if throughout find execution, the server gets lagged in serving its ordinary client requests or whatever, stop the execution of the cmd immediately by killing it from another ssh session or tty (if physically on the server).

2. Using a simple bash loop with rm command to delete "tons" of files

An alternative way is to use a bash loop, to print each of the files in the directory and issue /bin/rm on each of the loop elements (files) like so:

for i in *; do
rm -f $i;
done

If you'd like to print what you will be deleting add an echo to the loop:

# for i in $(echo *); do \
echo "Deleting : $i"; rm -f $i; \

The bash loop, worked like a charm in my case so I really warmly recommend this method, whenever you need to delete more than 500 000+ files in a directory.

3. Deleting multiple files with perl

Deleting multiple files with perl is not a bad idea at all.
Here is a perl one liner, to delete all files contained within a directory:

# perl -e 'for(<*>){((stat)[9]<(unlink))}'

If you prefer to use more human readable perl script to delete a multitide of files use delete_multple_files_in_dir_perl.pl

Using perl interpreter to delete thousand of files is quick, really, really quick.
I did not benchmark it on the server, how quick exactly is it, but I guess the delete rate should be similar to find command. Its possible even in some cases the perl loop is  quicker …

4. Using PHP script to delete a multiple files

Using a short php script to delete files file by file in a loop similar to above bash script is another option.
To do deletion  with PHP, use this little PHP script:

<?php
$dir = "/path/to/dir/with/files";
$dh = opendir( $dir);
$i = 0;
while (($file = readdir($dh)) !== false) {
$file = "$dir/$file";
if (is_file( $file)) {
unlink( $file);
if (!(++$i % 1000)) {
echo "$i files removed\n";
}
}
}
?>

As you see the script reads the $dir defined directory and loops through it, opening file by file and doing a delete for each of its loop elements.
You should already know PHP is slow, so this method is only useful if you have to delete many thousands of files on a shared hosting server with no (ssh) shell access.

This php script is taken from Steve Kamerman's blog . I would like also to express my big gratitude to Steve for writting such a wonderful post. His post actually become  inspiration for this article to become reality.

You can also download the php delete million of files script sample here

To use it rename delete_millioon_of_files_in_a_dir.php.txt to delete_millioon_of_files_in_a_dir.php and run it through a browser .

Note that you might need to run it multiple times, cause many shared hosting servers are configured to exit a php script which keeps running for too long.
Alternatively the script can be run through shell with PHP cli:

php -l delete_millioon_of_files_in_a_dir.php.txt.

5. So What is the "best" way to delete million of files on Linux?

In order to find out which method is quicker in terms of execution time I did a home brew benchmarking on my thinkpad notebook.

a) Creating 509072 of sample files.

Again, I used bash loop to create many thousands of files in order to benchmark.
I didn't wanted to put this load on a productive server and hence I used my own notebook to conduct the benchmarks. As my notebook is not a server the benchmarks might be partially incorrect, however I believe still .they're pretty good indicator on which deletion method would be better.

hipo@noah:~$ mkdir /tmp/test
hipo@noah:~$ cd /tmp/test;
hiponoah:/tmp/test$ for i in $(seq 1 509072); do echo aaaa >> $i.txt; done

I had to wait few minutes until I have at hand 509072  of files created. Each of the files as you can read is containing the sample "aaaa" string.

b) Calculating the number of files in the directory

Once the command was completed to make sure all the 509072 were existing, I used a find + wc cmd to calculate the directory contained number of files:

hipo@noah:/tmp/test$ find . -maxdepth 1 -type f |wc -l
509072
real 0m1.886s
user 0m0.440s
sys 0m1.332s

Its intesrsting, using an ls command to calculate the files is less efficient than using find:

hipo@noah:/tmp/test$ time ls -1 |wc -l
509072
real 0m3.355s
user 0m2.696s
sys 0m0.528s

c) benchmarking the different file deleting methods with time

– Testing delete speed of find

hipo@noah:/tmp/test$ time find . -maxdepth 1 -type f -delete
real 15m40.853s
user 0m0.908s
sys 0m22.357s

You see, using find to delete the files is not either too slow nor light quick.

– How fast is perl loop in multitude file deletion ?

hipo@noah:/tmp/test$ time perl -e 'for(<*>){((stat)[9]<(unlink))}'real 6m24.669suser 0m2.980ssys 0m22.673s

Deleting my sample 509072 took 6 mins and 24 secs. This is about 3 times faster than find! GO-GO perl 🙂
As you can see from the results, perl is a great and time saving, way to delete 500 000 files.

– The approximate speed deletion rate of of for + rm bash loop

hipo@noah:/tmp/test$ time for i in *; do rm -f $i; done
real 206m15.081s
user 2m38.954s
sys 195m38.182s

You see the execution took 195m en 38 secs = 3 HOURS and 43 MINUTES!!!! This is extremely slow ! But works like a charm as the running of deletion didn't impacted my normal laptop browsing. While the script was running I was mostly browsing through few not so heavy (non flash) websites and doing some other stuff in gnome-terminal) 🙂

As you can imagine running a bash loop is a bit CPU intensive, but puts less stress on the hard disk read/write operations. Therefore its clear using it is always a good practice when deletion of many files on a dedi servers is required.

b) my production server file deleting experience

On a production server I only tested two of all the listed methods to delete my files. The production server, where I tested is running Debian GNU / Linux Squeeze 6.0.3. There I had a task to delete few million of files.
The tested methods tried on the server were:

– The find . type -f -delete method.

– for i in *; do rm -f $i; done

The results from using find -delete method was quite sad, as the server almost hanged under the heavy hard disk load the command produced.

With the for script all went smoothly. The files were deleted for a long long time (like few hours), but while it was running, the server continued with no interruptions..

While the bash loop was running, the server load avarage kept at steady 4
Taking my experience in mind, If you're running a production, server and you're still wondering which delete method to use to wipe some multitude of files, I would recommend you go  the bash for loop + /bin/rm way. Yes, it is extremely slow, expect it run for some half an hour or so but puts not too much extra load on the server..

Using the PHP script will probably be slow and inefficient, if compared to both find and the a bash loop.. I didn't give it a try yet, but suppose it will be either equal in time or at least few times slower than bash.

If you have tried the php script and you have some observations, please drop some comment to tell me how it performs.

To sum it up;

Even though there are "hacks" to clean up some messy parsing directory full of few million of junk files, having such a directory should never exist on the first place.

Frankly, keeping millions of files within the same directory is very stupid idea.
Doing so will have a severe negative impact on a directory listing performance of your filesystem in the long term.

If you know better (more efficient) ways to delete a multitude of files in a dir please share in comments.

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Posted in Linux, Programming, System Administration | 12 Comments »

How to start a process in background and keep it running after the console / terminal is closed on Linux and FreeBSD

Tuesday, November 29th, 2011

The classical way to keep a process running in background after log out of a shell is using screen
Anyways using screen is not the only way to detach a running process , GNU / Linux and BSDs (Free, Open, Net BSDs) had a command nohup which aim is to run a command immune to hangups, with output to a non-tty

Let’s say one wants to keep track (log) constantly ICMP traffic to a certain host with ping command on a UNIX server / desktop which doesn’t have the screen manager … terminal emulation program installed. Achieving this task is possible with nohup cmd by backgrounding the ping process, like so:

guoi@host:~$ nohup ping google.com >ping.log &[1] 45931hipo@host:~$ nohup: ignoring input and redirecting stderr to stdout

Afterwards even after closing up the opened ssh session or console (tty) / terminal (pts) on which the ping process is background nohup prevents the ping to be sent kill SIGNAL so the process continues running in the background.

Later on to check in real time the statistics of the continuous ICMP ping requests tail, less, or cat can be used for example watching the tail:

hipo@host:~$ tail -f ping.log
64 bytes from fx-in-f106.1e100.net (74.125.39.106): icmp_req=562 ttl=51 time=44.0 ms
64 bytes from fx-in-f106.1e100.net (74.125.39.106): icmp_req=563 ttl=51 time=43.8 ms
64 bytes from fx-in-f106.1e100.net (74.125.39.106): icmp_req=564 ttl=51 time=43.3 ms
64 bytes from fx-in-f106.1e100.net (74.125.39.106): icmp_req=565 ttl=51 time=43.1 ms
64 bytes from fx-in-f106.1e100.net (74.125.39.106): icmp_req=566 ttl=51 time=43.4 ms
64 bytes from fx-in-f106.1e100.net (74.125.39.106): icmp_req=567 ttl=51 time=43.6 ms
I’m using Linux / BSD for quite a lot of time and never before put in use the nohup cmd I guess there are more ppl who never heard of this handy UNIX basic command. Hope I’m not the only one who never heard about it and its useful knowledge to someone out. Cheers 😉

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Posted in FreeBSD, Linux, System Administration | 1 Comment »