Linux Commands

 month = $(date +%b) ; Apr

month = $(date +%B); April

yesterday = $( date -d  '-1 day' +'%Y_%m_%d') ; 2023_04_08

nth_day = $(date -d '-n day' +'%Y/%m/%d') ; 2023/04/08

network management in oracle linux 8 and later:-

Note:- It is mandatory to have GUI in case of  network restart

**restart network on oracle linux 8 and later :-
# systemctl restart NetworkManager
# nmcli networking off
# nmcli networking on

** to change file extensions in linux:

[root@localhost ~]# ls

file.txt

[root@localhost ~]# mv file{.txt,.bak}

[root@localhost ~]# ls

file.bak 

* if you want to delete all files except some use below:-

$ find . ! -name 'file_name' ! -name 'file_name' -delete

*** to find dbf files 

$ ls | grep -e "^[[:digit:]]\{4\}\+\_[[:digit:]]\{2\}\+\_[[:digit:]]\{2\}\+\_[[:digit:]]\{4\}\+\_dbf"

2023_08_13_2230_dbf_s99793_p1

2023_08_13_2230_dbf_s99794_p1

2023_08_13_2230_dbf_s99795_p1

2023_08_13_2230_dbf_s99796_p1

2023_08_13_2230_dbf_s99797_p1

2023_08_13_2230_dbf_s99798_p1

2023_08_13_2230_dbf_s99799_p1

\+\ ----> to add metacharacters like "-/_"

$ ls -lrth | awk '{print $9}' | grep -e "^[[:digit:]]\{4\}\+\_[[:digit:]]\{2\}\+\_[[:digit:]]\{2\}\+\_[[:digit:]]\{4\}\+\_[[:alpha:]]\{3\}\+\_[[:alnum:]]\{6\}\+\_[[:alnum:]]\{2\}"

2023_08_13_2230_dbf_s99798_p1

2023_08_13_2230_dbf_s99799_p1

# view selinux setting 

# sestatus 

# cat /etc/selinux/config

********************************************

Add user to sudoers list:-

( /etc/sudoers)

--------------------------------

# sudo visudo        #--------> to open /etc/sudoers in vim 

# User privilege specification

root    ALL=(ALL:ALL) ALL

<username>  ALL=(ALL:ALL)  ALL