Linux OS Dev

Kernel programming for Linux operating systems can be done with many different languages; C, C++, Python, Perl and Java, which are some of the most common languages used.There are also many different varieties of Linux, such as Ubuntu, Fedora and OpenSUSE.

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I have an RHEL5 VM that reboots on kernel panics. The VM hangs while rebooting at different stages of the bootup process.
I noticed the console shows the cursor blinking but stays stuck booting up and does not progress.

Any ideas on how to troubleshoot? The blinking cursor indicates the system is hung, correct?
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file create error on below site


https://www.tutorialspoint.com/execute_bash_online.php

please advise how to create some files and practice grep commands there

any other online free tools to practice unix.

please advise
fileCreate.png
0
what is the meaning of below command

zgrep 'CUSTOMERPASS' abcd.20180719.gz|grep -v 'Trials: 1'|less



Is there is single link, tutorial or video tutorial where i can find above kind of command
and
count command

more
less
grep
etc.

alll commonly used commands like above
why we need | before less?

Please advise
0
server times out

i have 15 production unix server instances to check logs same time

when i am on one monitor other monitor times out in every 15 minutes

if i type
tail -f logfile


does it still times out on me

i cannot change time out setting myself

just looking for some work around so that i do not have to enter username and password all over again
0
transactions search in unix logs


in the unix logs of transactions each transaction has bunch of values like

transaction_id|transaction_time|transaction_description|transaction_type| ......etc



if i want to display only the transactions that took more than say 30 minutes and whose transaction_type is "sell"

how do i frame my grep command for that

any sample queries, links, resources, sample video tutorials on this

Please advise
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when i open with winscp that opens old stale file compared to putty opening of same file say xyz.ccfg

i wonder why winscp does not show recent changs?

please advise
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how to import sessions from putty or mputty to securecrt.
https://www.vandyke.com/products/securecrt/

I recently installed securecrt not sure how to import all existing conections to different servers on different environments that are present in putty to winscp.

any tips on effective use of securecrt as i am new to it

Please advise
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1. Can someone explain me if there is any changes in .cloginrc file, I need to run the rancid-cvs and rancid-run,
2. When i am trying to login i can see that the username is not pulling from what is there in .cloginrc.

For Eg:
(Under my clogin file)
I have mentioned
add user 1x.x.x User1
add password 1x.x.x       {password}
add method 1x.x.x telnet ssh

But when i am trying to login, i can see that username is in rancid. I am not sure why its happening. And to make sure that if try firewall login or normal login, its going with actual username only
0
on my windows 10 machine after installing oracle virtua box and centos on top of it while starting getting below error


Failed to open a session for the virtual machine centos.

The virtual machine 'centos' has terminated unexpectedly during startup with exit code 1 (0x1).  More details may be available in 'C:\Users\saiganesh\VirtualBox VMs\centos\Logs\VBoxHardening.log'.

Result Code: E_FAIL (0x80004005)
Component: MachineWrap
Interface: IMachine {b2547866-a0a1-4391-8b86-6952d82efaa0}

i tried on other laptop i do not see red hat 64 some reason but shows red hat 32 bit

Please advise
centos.png
centos.png
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how to remember shell history and how to save unix queries for future use and share with the team

$HISTSIZE can be increased to unlimited size?

how to type attached l character

please advise
L_char.png
0
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how below commands are different

su department (when i do pwd here says department)
vs
su - department(when i do pwd here says /home/department)

when i do below

su -c 'echo $echo  $DEPARTMENT_HOME' department
it does not work

when i do below

su -c 'echo $echo  $DEPARTMENT_HOME'  - department
it does work. Please advise the difference.

what is difference between
department and  /home/department

how su and sudo are different?

how can there is depearment inside home as well as outside at top level again?

what is visudo and sudoers file or folder?

Please advise
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difference between below process killing signals

kill -15 123

vs

kill -TERM 123
vs

kill -9 123


how foreground and background processes are different and how to kill or suspend them?
is PID is always 4 digit or it can be 10 digit etc?

how job and process different?
how to distinguish between background and foreground jobs?

when i say
jobs

it simply shows 5 different jobs one with + other with -

but does not show whether background or foreground?

i have a job running in background i brought it to foreground and stopped it.
when i moved it again to background it automatically moved to RUNNING status? how this is possible?
how terminated suspended and killed etc are different?
Please advise
0
We have setup OpenVas in our infrastructure. We were able to run it in order to scan assessments reports on VM's within our infrastructure. However the results of the scans is very long and complete. We would like to filter that same report in order to only have results of the High severity reports.

Any idea on what would be the most effective approach to filter the Greenbone scans?
0
What awstat format i need for that type af log from ftp server
....
....
Feb 26 13:47:24 ftp sshd[1260]: Disconnected from 115.238.245.6 port 36575 [preauth]
Feb 26 13:47:24 ftp sshd[1260]: PAM 2 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=115.238.245.6  user=root
...
....

i used all 1 ...4 then i used :
LogFormat= "%time3 %other %method %url %logname %host %code %other"
or
LogFormat= "%time3 %other %host %bytesd %url %other %other %method %other %logname %other %code %other %other"

all says  
found 401 dropped records
2000 corrupted records
...
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how can i send out put from own scripts to nagios 4.3.4
i have a scrip to count som special open files. in this. in this open file 10 of them are contain localhost in path of open files
den command like check_nrpe -H localhost(or ip number) -c check_own_scripts
count only all files which is contain localhost in path itmeans return 10
but when run ./check_own_sripts returns 800.
what i did wrong here. it's just simple scripts
lsof -p pid | wc -l
0
I am unable to roll back my recent updates.

[root@ansible ~]# yum history
Loaded plugins: product-id, search-disabled-repos, subscription-manager
ID     | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
     7 | root <root>              | 2018-02-28 13:11 | Erase          |    2
     6 | root <root>              | 2018-02-27 18:12 | I, O, U        |  309 EE
     5 | root <root>              | 2017-11-18 12:57 | I, U           |   32
     4 | root <root>              | 2017-11-16 01:13 | Install        |   33
     3 | root <root>              | 2017-11-16 01:10 | Install        |   23
     2 | root <root>              | 2017-11-05 10:37 | Install        |   13 E<
     1 | System <unset>           | 2017-11-05 10:01 | Install        |  385 >
history list


[root@ansible ~]# yum history undo 6
Loaded plugins: product-id, search-disabled-repos, subscription-manager

..........(output omitted)
---> Package zlib.i686 0:1.2.7-17.el7 will be erased
--> Processing Conflict: kernel-3.10.0-693.17.1.el7.x86_64 conflicts kexec-tools < 2.0.14-3
--> Finished Dependency Resolution
Error: kernel conflicts with kexec-tools-2.0.7-50.el7.x86_64
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest
0
Hello, how can I start a container and open new ports?
0
saiganesh@LAPTOP-EJBON1NM ~
$ mkdir gp

saiganesh@LAPTOP-EJBON1NM ~
$ cp * gp/
[b]cp: -r not specified; omitting directory 'gp'[/b]

saiganesh@LAPTOP-EJBON1NM ~
$ cd gp

saiganesh@LAPTOP-EJBON1NM ~/gp

Open in new window

why i am geting above error while copying all files to gp directory? please advise
i want to try rm and rmdir also
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I am getting this error message, when I was trying to run rpmbuild --rebuild lin_tape-3.0.23-1.src.rpm on Red Hat Linux 7.4 (Kernel version: 3.10.0-693.1.1.el7.x86_64). Can some one let me know what is problem and what should be the proper procedure to fix it. Here is the output mentioned below,

#rpmbuild --rebuild lin_tape-3.0.23-1.src.rpm
Installing lin_tape-3.0.23-1.src.rpm
Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.sCvFVM
+ umask 022
+ cd /root/rpmbuild/BUILD
+ cd /root/rpmbuild/BUILD
+ rm -rf lin_tape-3.0.23
+ /usr/bin/gzip -dc /root/rpmbuild/SOURCES/lin_tape-3.0.23.tgz
+ /usr/bin/tar -xf -
+ STATUS=0
+ '[' 0 -ne 0 ']'
+ cd lin_tape-3.0.23
+ /usr/bin/chmod -Rf a+rX,u+w,g-w,o-w .
+ exit 0
Executing(%build): /bin/sh -e /var/tmp/rpm-tmp.KGligF
+ umask 022
+ cd /root/rpmbuild/BUILD
+ cd lin_tape-3.0.23
++ echo x86_64-redhat-linux-gnu
++ cut -f 1 -d -
+ p=x86_64
+ '[' x86_64 == i386 ']'
+ '[' x86_64 == i586 ']'
+ '[' x86_64 == i686 ']'
+ '[' x86_64 == ppc64 ']'
+ '[' x86_64 == powerpc ']'
+ '[' x86_64 == powerpc64 ']'
+ '[' x86_64 == s390 ']'
+ '[' x86_64 == s390x ']'
+ '[' x86_64 == ia64 ']'
+ '[' x86_64 == x86_64 ']'
+ proc=AMD
+ make KERNEL=3.10.0-693.1.1.el7.x86_64 PROC=x86_64 SFMP=0 driver
make: Nothing to be done for `driver'.
+ exit 0
Executing(%install): /bin/sh -e /var/tmp/rpm-tmp.hQeoFx
+ umask 022
+ cd /root/rpmbuild/BUILD
+ '[' /root/rpmbuild/BUILDROOT/lin_tape-3.0.23-1.x86_64 '!=' / ']'
+ rm -rf …
0
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hi

How to Make The Text Cursor Automatically when i'm on console text ?
I use directly on boot the tty console and desactivate graphical mode.

Thanks for your reply,

someone talk me about : /etc/inittab, or /etc/fstab
But i don't think it's good idea to modify 2 by 5
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I am installing spacewalk on RHEL7.

I was following this article.

https://github.com/spacewalkproject/spacewalk/wiki/HowToInstall

I am getting the following error when i execute,
yum -y install spacewalk-postgresql


Error: Package: jboss-jstl-1.2-api-1.0.3-15.1.el7.noarch (epel)
           Requires: mvn(org.jboss.spec.javax.servlet:jboss-servlet-api_3.0_spec)
Error: Package: jboss-jstl-1.2-api-1.0.3-15.1.el7.noarch (epel)
           Requires: mvn(org.jboss.spec.javax.el:jboss-el-api_2.2_spec)
Error: Package: jpam-0.4-28.el7.x86_64 (spacewalk)
           Requires: apache-commons-beanutils
Error: Package: jboss-jsp-2.2-api-1.0.1-15.1.el7.noarch (epel)
           Requires: mvn(org.jboss.spec.javax.servlet:jboss-servlet-api_3.0_spec)
Error: Package: spacewalk-jpp-workaround-2.3.5-1.el7.noarch (spacewalk)
           Requires: apache-commons-validator
Error: Package: struts-1.3.10-14.1.el7.noarch (epel)
           Requires: mvn(commons-validator:commons-validator)
Error: Package: apache-commons-chain-1.2-12.1.el7.noarch (epel)
           Requires: mvn(commons-digester:commons-digester)
Error: Package: python-cheetah-2.4.4-4.el7.x86_64 (epel)
           Requires: python-pygments
Error: Package: spacewalk-jpp-workaround-2.3.5-1.el7.noarch (spacewalk)
           Requires: apache-commons-digester
Error: Package: jboss-jsp-2.2-api-1.0.1-15.1.el7.noarch (epel)
           Requires: mvn(org.jboss.spec.javax.el:jboss-el-api_2.2_spec)
Error: Package: …
0
--> Finished Dependency Resolution
Error: Package: spacewalk-taskomatic-2.7.115-1.el7.noarch (spacewalk)
           Requires: hibernate3 >= 3.6.10
           Available: hibernate3-3.2.4-1.SP1_CP01.9.jpp5.noarch (jpackage-generic)
               hibernate3 = 3.2.4-1.SP1_CP01.9.jpp5
Error: Package: spacewalk-java-2.7.115-1.el7.noarch (spacewalk)
           Requires: tomcat-taglibs-standard
Error: Package: spacewalk-java-2.7.115-1.el7.noarch (spacewalk)
           Requires: hibernate3-ehcache >= 3.6.10
Error: Package: spacewalk-java-2.7.115-1.el7.noarch (spacewalk)
           Requires: hibernate3-c3p0 >= 3.6.10
Error: Package: cglib-2.1.3-4.jpp5.noarch (jpackage-generic)
           Requires: asm >= 1.5.3
           Available: asm-1.5.3-7.jpp5.noarch (jpackage-generic)
               asm = 1.5.3-7.jpp5
Error: Package: spacewalk-taskomatic-2.7.115-1.el7.noarch (spacewalk)
           Requires: hibernate3-c3p0 >= 3.6.10
Error: Package: spacewalk-taskomatic-2.7.115-1.el7.noarch (spacewalk)
           Requires: concurrent >= 1.3.4-21
           Available: concurrent-1.3.4-9.jpp5.noarch (jpackage-generic)
               concurrent = 1.3.4-9.jpp5
Error: Package: spacewalk-java-2.7.115-1.el7.noarch (spacewalk)
           Requires: apache-commons-el
Error: Package: spacewalk-taskomatic-2.7.115-1.el7.noarch (spacewalk)
           Requires: hibernate3-ehcache >= 3.6.10
Error: Package: spacewalk-java-2.7.115-1.el7.noarch (spacewalk)
           Requires: hibernate3 …
0
Hello ,

I have a problem with interfaces on a multihomed topology. My interfaces can not ping each other and can not ping theirselves too
sysctl as given below.

But it is able to ping the interface ip when i directly write ping 37.123.98.142 , if the both interface are not able to ping this interface's ip how does it ping it or from where ?

I have to let them have access each other how shoud i do it ?

Note: loopback interface activated
Note2: em interfaces are all down

[root@spd network-scripts]# sysctl -p
net.ipv4.ip_forward = 1
net.ipv4.conf.p1p1.rp_filter = 2
net.ipv4.conf.p1p2.rp_filter = 2
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.default.rp_filter = 2
net.ipv4.conf.lo.rp_filter = 2
net.ipv4.conf.p1p1.accept_local = 1
net.ipv4.conf.p1p2.accept_local = 1
net.ipv4.conf.all.accept_local = 1
net.ipv4.conf.default.accept_local = 1
net.ipv4.conf.lo.accept_local = 1
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.p1p2.arp_filter = 0
net.ipv4.conf.p1p1.arp_filter = 0
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.p1p1.arp_announce = 2
net.ipv4.conf.p1p2.arp_announce = 2

Open in new window


PING 37.123.98.142 (37.123.98.142) from 37.123.98.142 p1p1: 56(84) bytes of data.

^C
--- 37.123.98.142 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2055ms

[root@spd network-scripts]# ping -I p1p1 37.123.98.138
PING 37.123.98.138 (37.123.98.138) from 37.123.98.142 p1p1: 56(84) bytes of data.

^C
--- 37.123.98.138 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3064ms

[root@spd network-scripts]# ping -I p1p2 37.123.98.138
PING 37.123.98.138 (37.123.98.138) from 37.123.98.138 p1p2: 56(84) bytes of data.

^C
--- 37.123.98.138 ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1038ms

[root@spd network-scripts]# ping -I p1p2 37.123.98.142
PING 37.123.98.142 (37.123.98.142) from 37.123.98.138 p1p2: 56(84) bytes of data.

^C
--- 37.123.98.142 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2060ms

Open in new window


[root@spd network-scripts]# ping 37.123.98.142
PING 37.123.98.142 (37.123.98.142) 56(84) bytes of data.
64 bytes from 37.123.98.142: icmp_seq=1 ttl=64 time=0.019 ms
64 bytes from 37.123.98.142: icmp_seq=2 ttl=64 time=0.022 ms
64 bytes from 37.123.98.142: icmp_seq=3 ttl=64 time=0.017 ms
64 bytes from 37.123.98.142: icmp_seq=4 ttl=64 time=0.015 ms

Open in new window




Open in new window

0
[root@localhost httpd-2.4.27]# ./configure
checking for chosen layout... Apache
checking for working mkdir -p... yes
checking for grep that handles long lines and -e... /bin/grep
checking for egrep... /bin/grep -E
checking build system type... x86_64-pc-linux-gnu
checking host system type... x86_64-pc-linux-gnu
checking target system type... x86_64-pc-linux-gnu
configure:
configure: Configuring Apache Portable Runtime library...
configure:
checking for APR... no
configure: error: APR not found.  Please read the documentation.
0
Hello,

What is the difference between puppet class vs module?
0

Linux OS Dev

Kernel programming for Linux operating systems can be done with many different languages; C, C++, Python, Perl and Java, which are some of the most common languages used.There are also many different varieties of Linux, such as Ubuntu, Fedora and OpenSUSE.