Команды для линукс centos

For older version of centOS:

ifconfig | grep "inet " | grep -v 127.0.0.1 | awk '' 

netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

-a, --all Show both listening and non-listening (for TCP this means established connections) sockets. With the --interfaces option, show interfaces that are not up

--numeric , -n Show numerical addresses instead of trying to determine symbolic host, port or user names.

-p, --program Show the PID and name of the program to which each socket belongs.

CentOS 7 netstat, which is part of the package net-tools has been officially deprecated, so you should be using ss (part of the package iproute2 ), going forward.

-l, --listening Display only listening sockets (omitted by default).

-n, --numeric Do not try to resolve service names.

-p, --processes Show process using socket.

-t, --tcp Display TCP sockets.

journalctl -u nginx.service --since today 

Prints the names and values of all currently defined environment variables

Examine the value of a particular variable

The dollar sign $ can actually be used to combine the values of environment variables in many shell commands. For example, the following command can be used to list the contents of the "Desktop" directory within the current user's home directory.

System wide environment variables

sudo -H nano /etc/environment 

It's important to do exact the way above, and not as the root user, as it may cause problems like unable to login. If you use normal sudo to start graphical applications (including editors e.g. gedit), sometimes it results in the configuration files being owned by root, read more about it here.

The only time the file is read is on login, when the PAM stack is activated – specifically pam_env.so, which reads the file.

Logging out and back in would apply the changes – and in fact you must do this if you want all your processes to receive the new environment. All other solutions will only apply the environment to the single shell process, but not to anything you launch through the GUI including new terminal windows.

show which app will be run by default

show the manual for command

• cd dir - change directory to dir
• cd – change to home
• pwd – show current directory
• mkdir dir – create a directory dir
• rm file – delete file
• rm -r dir – delete directory dir
• rm -f file – force remove file
• rm -rf dir – force remove directory dir *
• cp file1 file2 – copy file1 to file2
• cp -r dir1 dir2 – copy dir1 to dir2; create dir2 if it doesn't exist
• mv file1 file2 – rename or move file1 to file2 if file2 is an existing directory, moves file1 into directory file2
• touch file – create or update file
• cat > file – places standard input into file
• more file – output the contents of file
• head file – output the first 10 lines of file
• tail file – output the last 10 lines of file
• tail -f file – output the contents of file as it grows, starting with the last 10 lines

show hidden files with -a , show details with -l

Determine file type, i.e. check if somthing is a symbolic link.

Counting Files in the Current Directory

This uses wc to do a count of the number of lines (-l) in the output of ls -1. http://tldp.org/HOWTO/Bash-Prompt-HOWTO/x700.html

• chmod octal file – change the permissions of file to octal, which can be found separately for user, group, and world by adding:
• 4 – read (r)
• 2 – write (w)
• 1 – execute (x)

• chmod 777 – read, write, execute for all
• chmod 755 – rwx for owner, rx for group and world

• tar cf file.tar files – create a tar named file.tar containing files
• tar xf file.tar – extract the files from file.tar
• tar czf file.tar.gz files – create a tar with Gzip compression
• tar xzf file.tar.gz – extract a tar using Gzip
• tar cjf file.tar.bz2 – create a tar with Bzip2 compression
• tar xjf file.tar.bz2 – extract a tar using Bzip2
• gzip file – compresses file and renames it to file.gz
• gzip -d file.gz – decompresses file.gz back to file

• top – display all running processes
• kill pid – kill process id pid
• killall proc – kill all processes named proc *
• bg – lists stopped or background jobs; resume a stopped job in the background
• fg – brings the most recent job to foreground
• fg n – brings job n to the foreground

Display your currently active processes

Show full command including arguments.

• ping host – ping host and output results
• whois domain – get whois information for domain
• dig domain – get DNS information for domain
• dig -x host – reverse lookup host
• wget file – download file
• wget -c file – continue a stopped download

Ubuntu apt update apt upgrade apt install pkg

Node.js, Javascript package manager

grep "denied" /var/log/audit/audit.log 

Graph with gnuplot interactively:

apt update apt install gnuplot-x11 gnuplot 

# SET TERMINAL set term gif set output 'frequency.gif' # set title "Word Frequency" # Axes label # set xlabel "Words" # set ylabel "Frequency" set xtics rotate by -90 plot "frequency.dat" using 1:xticlabels(2) with boxes

Create symbolic link link to file

Without -s , then create hard link.

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