In this article, I am going to share
with you the collection of several interesting, unique command-line tricks.
If you are a Linux administrator or Linux user, let’s start with some Linux command line tricks to enhance the creativeness at the terminal.
If you are a Linux administrator or Linux user, let’s start with some Linux command line tricks to enhance the creativeness at the terminal.
1) Only one user to
allow to switch on root account as an administration user.
Sometimes, a sys admin have some kind
of the requirements to allow only one user to switch on root account. Use the
following steps,
a.) Add user on “wheel” group
#gpasswd -a <user name>
<group name> (Where, “a” Add the user to
the named group.)
[root@server1
~]# gpasswd -a gaurav wheel
Adding
user gaurav to group wheel
[root@server1
~]# cat /etc/group | grep wheel
wheel:x:10:gaurav
[root@server1
~]#
We added “gaurav” user on “wheel”
group.
b.) Edit the /etc/pam.d/su file.
#vim /etc/pam.d/su Uncomment the following line(line no. 6).
#%PAM-1.0
auth
sufficient pam_rootok.so
#
Uncomment the following line to implicitly trust users in the "wheel"
group.
#auth
sufficient pam_wheel.so trust use_uid
#
Uncomment the following line to require a user to be in the "wheel"
group.
auth
required pam_wheel.so use_uid
auth
substack system-auth
auth
include postlogin
account
sufficient pam_succeed_if.so uid = 0 use_uid
quiet
account
include system-auth
password
include system-auth
session
include system-auth
session
include postlogin
session
optional pam_xauth.so
~
~
:wq
c.) Now try to check with user
login.
[gaurav@server1
~]$ su - root
Password:
Last
login: Fri Sep 23 06:13:30 EDT 2016 from 192.168.1.5 on pts/1
[root@server1
~]# exit
logout
[gaurav@server1
~]$ su - anil
Password:
Last
login: Mon Sep 19 11:32:05 EDT 2016 on pts/1
[anil@server1
~]$ su - root
Password:
su:
Permission denied
[anil@server1
~]$
As shown, “gaurav” user can
switch to root account but “anil” user not able to login on root account
and showing Permission denied.
2) Run the last
command as any user.
#!!
[root@server1
~]# cat /etc/group | grep wheel
wheel:x:10:gaurav
[root@server1
~]# !!
cat
/etc/group | grep wheel
wheel:x:10:gaurav
[root@server1
~]#
3) Find out the
current shell name.
You can identify your current shell
using following command, #echo $SHELL or echo $0
[root@server1
~]# echo $SHELL
/bin/bash
[root@server1
~]# echo $0
-bash
[root@server1
~]#
Where, “$SHELL” is the environment
variable that stores the name of current shell and “$0” shows the name of
program.
4) Some Tip and Tricks
for shutdown command.
# shutdown -r now or init 6
[root@server1
~]# shutdown -r now
PolicyKit
daemon disconnected from the bus.
We
are no longer a registered authentication agent.
Connection
to 192.168.1.10 closed by remote host.
It
will reboot the system.
#shutdown -h now or init 0
[root@server1
~]# shutdown -h now
It
will shutdown the server now (i.e power off)
# shutdown 06:45
[root@server1
~]# date
Fri
Sep 23 06:39:54 EDT 2016
[root@server1
~]# shutdown 06:45
Shutdown
scheduled for Fri 2016-09-23 06:45:00 EDT, use 'shutdown -c' to cancel.
[root@server1
~]#
System will shutdown at a specific
time.
# shutdown -c
[root@server1
~]# shutdown -c
Broadcast
message from root@server1 (Fri 2016-09-23 06:41:44 EDT):
The
system shutdown has been cancelled at Fri 2016-09-23 06:42:44 EDT!
[root@server1
~]#
As shown, system shutdown has been
cancelled.
5) Download rpm file
in specific directory by using downloadonly plugin.
Make specific directory and install
“yum-utils“. (If you want, how to configure the yum server, refer below
link.)
[root@server1
/]# mkdir /package
[root@server1
]# yum install yum-utils
Loaded
plugins: fastestmirror
Loading
mirror speeds from cached hostfile
Resolving
Dependencies
-->
Running transaction check
.
. . .
Transaction
Summary
============================================
Install
1 Package (+2 Dependent packages)
Total
download size: 607 k
Installed
size: 2.8 M
Is
this ok [y/d/N]: y
Now, Download the rpm file.
[root@server1
sambapackages]# yumdownloader --destdir=/package httpd
Loaded
plugins: fastestmirror
Loading
mirror speeds from cached hostfile
httpd-2.4.6-40.el7.centos.x86_64.rpm
| 2.7 MB 00:00:00
[root@server1
sambapackages]# ls
httpd-2.4.6-40.el7.centos.x86_64.rpm
[root@server1
sambapackages]# yumdownloader --destdir=/package samba
Loaded
plugins: fastestmirror
Loading
mirror speeds from cached hostfile
samba-4.2.3-10.el7.x86_64.rpm
| 601 kB 00:00:00
[root@server1
sambapackages]# ls
httpd-2.4.6-40.el7.centos.x86_64.rpm
samba-4.2.3-10.el7.x86_64.rpm
[root@server1
sambapackages]#
6) Close a terminal
without saving the history in Linux.
Your shell’s history is saved in the
file indicated by the HISTFILE variable.
#unset HISTFILE and #history -c (Where, “c” is used to Clear current session history.)
[gaurav@server1
~]$ unset HISTFILE
[gaurav@server1
~]$ free -m
total
used
free shared buff/cache
available
Mem:
993
96
688 6
207 747
Swap:
2047
0 2047
[gaurav@server1
~]$ w -u
07:11:23
up 33 min, 1 user, load average: 0.00, 0.01, 0.05
USER
TTY
FROM
LOGIN@ IDLE JCPU PCPU WHAT
root
pts/0 192.168.1.5
06:39 3.00s 0.35s 0.03s w -u
[gaurav@server1
~]$ exit
logout
[root@server1
~]# su - gaurav
Last
login: Fri Sep 23 07:10:57 EDT 2016 on pts/0
[gaurav@server1
~]$ history
1 history
[gaurav@server1
~]$
As show above, User “gaurav”
not find any history for previous session.
7) Make a Multiple
directories using one command.
Make some directories according to
the following in one command.
[root@server1
~]# mkdir -p
linux/{Storage/{san,nas,das},Network/{security,firewall,switch},Database/{oracle,mysql},Application/{tomcat,apache}}
[root@server1
~]# tree linux/
linux/
├──
Application
│
├── apache
│
└── tomcat
├──
Database
│
├── mysql
│
└── oracle
├──
Network
│
├── firewall
│
├── security
│
└── switch
└──
Storage
├── das
├── nas
└── san
14
directories, 0 files
[root@server1
~]#
Note: “tee” or “ls -R” command is used to check the
status.If “tree” package is not installed then install it, using ” yum
install -y tree” command.
8) check the
system’s reboot date and time.
#who -b
[root@server1
~]# who -b
system boot 2016-09-23 06:38
[root@server1
~]#
#last reboot
[root@server1
~]# last reboot
reboot
system boot 3.10.0-327.el7.x Fri Sep 23 06:38 - 07:16
(00:38)
reboot
system boot 3.10.0-327.el7.x Fri Sep 23 05:59 - 07:16
(01:17)
reboot
system boot 3.10.0-327.el7.x Fri Sep 23 05:56 - 07:16 (01:20)
9) Set Hostname
permanenelty in centos7/rhel7/fedora22.
#hostnamectl set-hostname
<hostname> (Where, hostnamectl is used to
control the system hostname).
[root@localhost
~]# hostname
localhost
[root@localhost
~]# hostnamectl set-hostname server1
[root@localhost
~]# hostname
server1
[root@localhost
~]#
Note: Re-login on the session, it will display “server1”
instead of “localhost”.
10) Delete the files
within the ranges between 20 to 100 days.
# find <directory location>
-mtime +20 -mtime -100 -iname “*.dbf” -delete
[root@server1
log]# date
Fri
Sep 23 16:58:50 EDT 2016
[root@server1
log]# ll
total
0
-rw-r--r--.
1 root root 0 Aug 2 18:01 aug1.dbf
-rw-r--r--.
1 root root 0 Aug 2 18:01 aug2.dbf
-rw-r--r--.
1 root root 0 Aug 2 18:01 aug3.dbf
-rw-r--r--.
1 root root 0 Aug 2 18:01 aug4.dbf
-rw-r--r--.
1 root root 0 Jul 15 18:00 jul1.dbf
-rw-r--r--.
1 root root 0 Jul 15 18:00 jul2.dbf
-rw-r--r--.
1 root root 0 Jul 15 18:00 jul3.dbf
-rw-r--r--.
1 root root 0 Jul 15 18:00 jul4.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep10.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep1.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep2.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep3.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep4.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep5.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep6.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep7.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep8.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep9.dbf
[root@server1
log]# find /root/log/ -mtime +20 -mtime -100 -iname "*.dbf" -delete
[root@server1
log]# ll
total
0
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep10.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep1.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep2.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep3.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep4.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep5.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep6.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep7.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep8.dbf
-rw-r--r--.
1 root root 0 Sep 23 16:57 sep9.dbf
[root@server1
log]#
As shown, all the files within the
ranges between 20 to 100 days are deleted.
11) Display the top ten running processes – sorted by memory usage.
# ps aux –sort -rss | head or ps -auxf | sort -nr -k 4 | head (if you want to read more about how to manage the process, refer below link. )
[root@server1 ]# ps aux --sort -rss | head
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
orabip 11877 0.0 11.3 9291280 3677596 ? Ss Aug17 4:52 ora_dbw0_BIP
orabip 11881 0.0 11.1 9291280 3624720 ? Ss Aug17 9:33 ora_dbw1_BIP
orabip 11885 0.0 11.0 9289232 3601160 ? Ss Aug17 8:20 ora_dbw2_BIP
root 12266 1.1 8.6 2843564 2818020 ? Ss 2015 7239:52 /usr/sap/hostctrl/exe/saposcol -l -w60 pf=/usr/sap/hostctrl/exe/host_profile
orabip 29913 0.0 8.3 9286900 2708388 ? Ss Aug23 26:51 oracleBIP (LOCAL=NO)
orabip 29883 0.0 7.9 9284840 2579220 ? Ss Aug23 22:14 oracleBIP (LOCAL=NO)
orabip 29887 0.0 7.9 9294964 2569704 ? Ss Aug23 16:45 oracleBIP (LOCAL=NO)
orabip 29921 0.0 7.6 9284856 2496932 ? Ss Aug23 23:27 oracleBIP (LOCAL=NO)
orabip 29879 0.0 7.5 9284836 2465056 ? Ss Aug23 17:10 oracleBIP (LOCAL=NO)
[root@server1 ]#
12) Add and remove Password Protection to a file using vim.
#vim -x <FILENAME>
[root@server1 ]# vim -x linux ↵
Once we enter the command, it will ask for the password.
Enter encryption key: ******
Enter same key again: ******
Now enter the content on this file.
Linux is the future.
future for linux.
future for linux.
Linux is the future.
~
~
:wq
Now next time you open the file it will ask the password.
[root@server1 ]# vim linux ↵
Need encryption key for "linux"
Enter encryption key: ******
Now, how to remove the password of file.
For removing the password of file, first open the file and type :set key= then, save it.
13) Find Duplicate Files on system.
Using below command you can find out the duplicate files based on size and MD5 hash.Let’s take the copy of “linux” file on “log” directory,So we have duplicate copy of “linux” file.
[root@server1 ~]# ls
anaconda-ks.cfg anaconda-screenshots linux linuxservers.doc log
[root@server1 ~]# cp -v linux log/
‘linux’ -> ‘log/linux’
[root@server1 ~]# find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate
59fbf515b5d267678cd4f33c569b3543 ./linux
59fbf515b5d267678cd4f33c569b3543 ./log/linux
f36c8d9f581e332e7c643579974df9f4 ./anaconda-screenshots/screenshot-0000.png
f36c8d9f581e332e7c643579974df9f4 ./anaconda-screenshots/screenshot-0001.png
[root@server1 ~]#
14) Without sorting Remove duplicate entries in a file and save on different file.
#awk ‘!x[$0]++’ <file>
Suppose we have file on which some duplicate entries are there, as follow
[root@server1 ~]# cat linux
Linux is the future.
future for linux.
future for linux.
Linux is the future.
[root@server1 ~]# awk '!x[$0]++' linux > linuxnew
[root@server1 ~]# cat linuxnew
Linux is the future.
future for linux.
[root@server1 ~]#
15) Find out the linux version on fedora/centos/rhel.
#cat /etc/*-release
[root@server1 ~]# cat /etc/*-release
CentOS Linux release 7.2.1511 (Core)
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"
CentOS Linux release 7.2.1511 (Core)
CentOS Linux release 7.2.1511 (Core)
[root@server1 ~]#
16) Execute the three command in simple command.
[root@server1 ~]# yum clean all && yum remove all && yum repolist all
Loaded plugins: fastestmirror
Cleaning repos: Centos7
Cleaning up everything
Cleaning up list of fastest mirrors
Loaded plugins: fastestmirror
No Match for argument: all
No Packages marked for removal
Loaded plugins: fastestmirror
Centos7 | 3.6 kB 00:00:00
(1/2): Centos7/group_gz | 155 kB 00:00:00
(2/2): Centos7/primary_db | 5.3 MB 00:00:00
Determining fastest mirrors
repo id repo name status
Centos7 Centos7 repository enabled: 9,007
repolist: 9,007
[root@server1 ~]#
17) 10 biggest files/folders for the current directory.
[root@server1 ~]# du -s * | sort -n | tail
18) Mount .iso file in UNIX/Linux.
[root@server1 ~]#ls
CentOS-7-x86_64-Minimal-1511(1).iso
[root@server1 ~]#mount -o loop /root/CentOS-7-x86_64-Minimal-1511\(1\).iso /mnt
mount: /dev/loop0 is write-protected, mounting read-only
[root@server1 ~]#ls
CentOS_BuildTag EFI EULA GPL images isolinux LiveOS Packages repodata RPM-GPG-KEY-CentOS-7 RPM-GPG-KEY-CentOS-Testing-7 TRANS.TBL
[root@server1 ~]#
19) Bind the /mnt directory with ftp pub dir.
As above, We mounted .iso file on /mnt directory.Now bind /mnt dir with pub dir.
[root@server1 ~]# mount --bind /mnt /var/ftp/pub/
Let’s see files in pub directory.
[root@server1 ~]# ftp 192.168.1.10
Connected to 192.168.1.10 (192.168.1.10).
220 (vsFTPd 3.0.2)
Name (192.168.1.10:root): ftp
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
227 Entering Passive Mode (192,168,1,10,156,103).
150 Here comes the directory listing.
drwxr-xr-x 5 0 0 94 Sep 18 05:39 pub
226 Directory send OK.
ftp> cd pub
250 Directory successfully changed.
ftp> ls
227 Entering Passive Mode (192,168,1,10,220,192).
150 Here comes the directory listing.
-r--r--r-- 1 0 0 14 Sep 17 10:15 CentOS_BuildTag
dr-xr-xr-x 3 0 0 4096 Sep 17 10:15 EFI
-r--r--r-- 1 0 0 215 Sep 17 10:15 EULA
-r--r--r-- 1 0 0 18009 Sep 17 10:15 GPL
dr-xr-xr-x 2 0 0 4096 Sep 17 10:16 LiveOS
dr-xr-xr-x 2 0 0 655360 Sep 17 10:23 Packages
-r--r--r-- 1 0 0 1690 Sep 17 10:23 RPM-GPG-KEY-CentOS-7
-r--r--r-- 1 0 0 1690 Sep 17 10:23 RPM-GPG-KEY-CentOS-Testing-7
-r--r--r-- 1 0 0 2883 Sep 17 10:23 TRANS.TBL
drwxr-xr-x 2 0 0 4096 Sep 17 10:37 centos7
dr-xr-xr-x 3 0 0 4096 Sep 17 10:16 images
dr-xr-xr-x 2 0 0 4096 Sep 17 10:16 isolinux
dr-xr-xr-x 2 0 0 4096 Sep 17 10:23 repodata
226 Directory send OK.
ftp>
20) Record the session of terminal.
You can use “script” command to record your session.
# script -a session1 (Where, “a” is used append the file).
[root@server1 ~]# script -a session1
Script started, file is session1
[root@server1 ~]# free -m
total used free shared buff/cache available
Mem: 993 103 504 6 384 695
Swap: 2047 0 2047
[root@server1 ~]# ps aux | sort -nk +4 | tail
root 3254 0.0 0.4 140772 5060 ? Ss 16:51 0:01 sshd: root@pts/0
root 502 0.0 0.4 46128 4824 ? Ss 16:08 0:00 /usr/lib/systemd/systemd-udevd
root 658 0.0 0.4 222116 4148 ? Ssl 16:09 0:00 /usr/sbin/rsyslogd -n
root 498 0.0 0.5 194664 5812 ? Ss 16:08 0:00 /usr/sbin/lvmetad -f
root 1 0.0 0.6 125816 6508 ? Ss 16:08 0:02 /usr/lib/systemd/systemd --switched-root --system --deserialize 21
root 725 0.0 0.7 434632 7908 ? Ssl 16:09 0:01 /usr/sbin/NetworkManager --no-daemon
polkitd 894 0.0 1.2 523524 12812 ? Ssl 16:09 0:00 /usr/lib/polkit-1/polkitd --no-debug
root 7939 0.0 1.5 110504 15756 ? S 17:46 0:00 /sbin/dhclient -d -q -sf /usr/libexec/nm-dhcp-helper -pf /var/run/dhclient-enp0s8.pid -lf /var/lib/NetworkManager/dhclient-d280a381-6718-46db-b168-90856f0d9ecf-enp0s8.lease -cf /var/lib/NetworkManager/dhclient-enp0s8.conf enp0s8
root 1260 0.0 1.6 553060 16300 ? Ssl 16:09 0:00 /usr/bin/python -Es /usr/sbin/tuned -l -P
root 664 0.0 2.2 323572 23276 ? Ssl 16:09 0:02 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
[root@server1 ~]# who
root pts/0 2016-09-23 07:20 (192.168.1.5)
root pts/1 2016-09-23 17:46
[root@server1 ~]# exit
exit
Script done, file is session1
[root@server1 ~]# ls
anaconda-ks.cfg linux linuxnew log session1
[root@server1 ~]#
Note: Session record is recored on “session1” file. You can check using “cat session1” command.
11) Display the top ten running processes – sorted by memory usage.
# ps aux –sort -rss | head or ps -auxf | sort -nr -k 4 | head (if you want to read more about how to manage the process, refer below link. )
[root@server1 ]# ps aux --sort -rss | head
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
orabip 11877 0.0 11.3 9291280 3677596 ? Ss Aug17 4:52 ora_dbw0_BIP
orabip 11881 0.0 11.1 9291280 3624720 ? Ss Aug17 9:33 ora_dbw1_BIP
orabip 11885 0.0 11.0 9289232 3601160 ? Ss Aug17 8:20 ora_dbw2_BIP
root 12266 1.1 8.6 2843564 2818020 ? Ss 2015 7239:52 /usr/sap/hostctrl/exe/saposcol -l -w60 pf=/usr/sap/hostctrl/exe/host_profile
orabip 29913 0.0 8.3 9286900 2708388 ? Ss Aug23 26:51 oracleBIP (LOCAL=NO)
orabip 29883 0.0 7.9 9284840 2579220 ? Ss Aug23 22:14 oracleBIP (LOCAL=NO)
orabip 29887 0.0 7.9 9294964 2569704 ? Ss Aug23 16:45 oracleBIP (LOCAL=NO)
orabip 29921 0.0 7.6 9284856 2496932 ? Ss Aug23 23:27 oracleBIP (LOCAL=NO)
orabip 29879 0.0 7.5 9284836 2465056 ? Ss Aug23 17:10 oracleBIP (LOCAL=NO)
[root@server1 ]#
12) Add and remove Password Protection to a file using vim.
#vim -x <FILENAME>
[root@server1 ]# vim -x linux ↵
Once we enter the command, it will ask for the password.
Enter encryption key: ******
Enter same key again: ******
Now enter the content on this file.
Linux is the future.
future for linux.
future for linux.
Linux is the future.
~
~
:wq
Now next time you open the file it will ask the password.
[root@server1 ]# vim linux ↵
Need encryption key for "linux"
Enter encryption key: ******
Now, how to remove the password of file.
For removing the password of file, first open the file and type :set key= then, save it.
13) Find Duplicate Files on system.
Using below command you can find out the duplicate files based on size and MD5 hash.Let’s take the copy of “linux” file on “log” directory,So we have duplicate copy of “linux” file.
[root@server1 ~]# ls
anaconda-ks.cfg anaconda-screenshots linux linuxservers.doc log
[root@server1 ~]# cp -v linux log/
‘linux’ -> ‘log/linux’
[root@server1 ~]# find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate
59fbf515b5d267678cd4f33c569b3543 ./linux
59fbf515b5d267678cd4f33c569b3543 ./log/linux
f36c8d9f581e332e7c643579974df9f4 ./anaconda-screenshots/screenshot-0000.png
f36c8d9f581e332e7c643579974df9f4 ./anaconda-screenshots/screenshot-0001.png
[root@server1 ~]#
14) Without sorting Remove duplicate entries in a file and save on different file.
#awk ‘!x[$0]++’ <file>
Suppose we have file on which some duplicate entries are there, as follow
[root@server1 ~]# cat linux
Linux is the future.
future for linux.
future for linux.
Linux is the future.
[root@server1 ~]# awk '!x[$0]++' linux > linuxnew
[root@server1 ~]# cat linuxnew
Linux is the future.
future for linux.
[root@server1 ~]#
15) Find out the linux version on fedora/centos/rhel.
#cat /etc/*-release
[root@server1 ~]# cat /etc/*-release
CentOS Linux release 7.2.1511 (Core)
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"
CentOS Linux release 7.2.1511 (Core)
CentOS Linux release 7.2.1511 (Core)
[root@server1 ~]#
16) Execute the three command in simple command.
[root@server1 ~]# yum clean all && yum remove all && yum repolist all
Loaded plugins: fastestmirror
Cleaning repos: Centos7
Cleaning up everything
Cleaning up list of fastest mirrors
Loaded plugins: fastestmirror
No Match for argument: all
No Packages marked for removal
Loaded plugins: fastestmirror
Centos7 | 3.6 kB 00:00:00
(1/2): Centos7/group_gz | 155 kB 00:00:00
(2/2): Centos7/primary_db | 5.3 MB 00:00:00
Determining fastest mirrors
repo id repo name status
Centos7 Centos7 repository enabled: 9,007
repolist: 9,007
[root@server1 ~]#
17) 10 biggest files/folders for the current directory.
[root@server1 ~]# du -s * | sort -n | tail
18) Mount .iso file in UNIX/Linux.
[root@server1 ~]#ls
CentOS-7-x86_64-Minimal-1511(1).iso
[root@server1 ~]#mount -o loop /root/CentOS-7-x86_64-Minimal-1511\(1\).iso /mnt
mount: /dev/loop0 is write-protected, mounting read-only
[root@server1 ~]#ls
CentOS_BuildTag EFI EULA GPL images isolinux LiveOS Packages repodata RPM-GPG-KEY-CentOS-7 RPM-GPG-KEY-CentOS-Testing-7 TRANS.TBL
[root@server1 ~]#
19) Bind the /mnt directory with ftp pub dir.
As above, We mounted .iso file on /mnt directory.Now bind /mnt dir with pub dir.
[root@server1 ~]# mount --bind /mnt /var/ftp/pub/
Let’s see files in pub directory.
[root@server1 ~]# ftp 192.168.1.10
Connected to 192.168.1.10 (192.168.1.10).
220 (vsFTPd 3.0.2)
Name (192.168.1.10:root): ftp
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
227 Entering Passive Mode (192,168,1,10,156,103).
150 Here comes the directory listing.
drwxr-xr-x 5 0 0 94 Sep 18 05:39 pub
226 Directory send OK.
ftp> cd pub
250 Directory successfully changed.
ftp> ls
227 Entering Passive Mode (192,168,1,10,220,192).
150 Here comes the directory listing.
-r--r--r-- 1 0 0 14 Sep 17 10:15 CentOS_BuildTag
dr-xr-xr-x 3 0 0 4096 Sep 17 10:15 EFI
-r--r--r-- 1 0 0 215 Sep 17 10:15 EULA
-r--r--r-- 1 0 0 18009 Sep 17 10:15 GPL
dr-xr-xr-x 2 0 0 4096 Sep 17 10:16 LiveOS
dr-xr-xr-x 2 0 0 655360 Sep 17 10:23 Packages
-r--r--r-- 1 0 0 1690 Sep 17 10:23 RPM-GPG-KEY-CentOS-7
-r--r--r-- 1 0 0 1690 Sep 17 10:23 RPM-GPG-KEY-CentOS-Testing-7
-r--r--r-- 1 0 0 2883 Sep 17 10:23 TRANS.TBL
drwxr-xr-x 2 0 0 4096 Sep 17 10:37 centos7
dr-xr-xr-x 3 0 0 4096 Sep 17 10:16 images
dr-xr-xr-x 2 0 0 4096 Sep 17 10:16 isolinux
dr-xr-xr-x 2 0 0 4096 Sep 17 10:23 repodata
226 Directory send OK.
ftp>
20) Record the session of terminal.
You can use “script” command to record your session.
# script -a session1 (Where, “a” is used append the file).
[root@server1 ~]# script -a session1
Script started, file is session1
[root@server1 ~]# free -m
total used free shared buff/cache available
Mem: 993 103 504 6 384 695
Swap: 2047 0 2047
[root@server1 ~]# ps aux | sort -nk +4 | tail
root 3254 0.0 0.4 140772 5060 ? Ss 16:51 0:01 sshd: root@pts/0
root 502 0.0 0.4 46128 4824 ? Ss 16:08 0:00 /usr/lib/systemd/systemd-udevd
root 658 0.0 0.4 222116 4148 ? Ssl 16:09 0:00 /usr/sbin/rsyslogd -n
root 498 0.0 0.5 194664 5812 ? Ss 16:08 0:00 /usr/sbin/lvmetad -f
root 1 0.0 0.6 125816 6508 ? Ss 16:08 0:02 /usr/lib/systemd/systemd --switched-root --system --deserialize 21
root 725 0.0 0.7 434632 7908 ? Ssl 16:09 0:01 /usr/sbin/NetworkManager --no-daemon
polkitd 894 0.0 1.2 523524 12812 ? Ssl 16:09 0:00 /usr/lib/polkit-1/polkitd --no-debug
root 7939 0.0 1.5 110504 15756 ? S 17:46 0:00 /sbin/dhclient -d -q -sf /usr/libexec/nm-dhcp-helper -pf /var/run/dhclient-enp0s8.pid -lf /var/lib/NetworkManager/dhclient-d280a381-6718-46db-b168-90856f0d9ecf-enp0s8.lease -cf /var/lib/NetworkManager/dhclient-enp0s8.conf enp0s8
root 1260 0.0 1.6 553060 16300 ? Ssl 16:09 0:00 /usr/bin/python -Es /usr/sbin/tuned -l -P
root 664 0.0 2.2 323572 23276 ? Ssl 16:09 0:02 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
[root@server1 ~]# who
root pts/0 2016-09-23 07:20 (192.168.1.5)
root pts/1 2016-09-23 17:46
[root@server1 ~]# exit
exit
Script done, file is session1
[root@server1 ~]# ls
anaconda-ks.cfg linux linuxnew log session1
[root@server1 ~]#
Note: Session record is recored on “session1” file. You can check using “cat session1” command.
No comments:
Post a Comment