Category: Linux

  • Comment multiple lines in vim

    To comment multiple lines in vim, first select the line in visual mode.

    To change mode to visual mode, type

    v

    Now use j/k keys to select lines of text you need to comment.

    To comment

    To comment, use :norm command.

    :norm i#

    This will insert # to start of every line.

    When you type :norm, in visual mode, you will see 

    :'<,'>norm i#

    Uncomment

    To uncomment, select the lines in visual mode. Then run

    :norm x

    this will delete first chars from every selected lines.

    Method 2

    You can use CTRL + V, this will select first char only.

    To comment

    1) Get into VISUAL_BLOCK mode by pressing CTRL + V
    2) use j/k keys to select lines to comment.
    3) Press SHIFT + I, now type #
    4) Press ESC

    To uncomment

    1) Get into VISUAL_BLOCK mode by pressing CTRL + V
    2) use j/k keys to select lines to comment.
    3) Press x

  • Install InterPlanetary File System (IPFS)

    Install InterPlanetary File System (IPFS)

    InterPlanetary File System (IPFS) is a peer-peer Distributed file system allow nodes to join and share files.

    https://ipfs.io

    To install IPFS, download latest version of IPFS for your Operating System from

    https://dist.ipfs.io/#go-ipfs

    For Ubuntu/Linux

    cd /usr/loca/src
wget https://dist.ipfs.io/go-ipfs/v0.4.18/go-ipfs_v0.4.18_linux-amd64.tar.gz
tar xvf go-ipfs_v0.4.18_linux-amd64.tar.gz
cd go-ipfs
./install.sh

    Once installed, initialize IPFS server with command

    ipfs init --profile server

    Start ipfs server with

    ipfs daemon

    You can see all peers connected to your server with command

    ipfs swarm peers

  • Yum disable a repository

    To disable a repository, run

    yum-config-manager --disable REPO_NAME_HERE

    To list all enabled repository, run

    yum repolist

  • Large file upload in PHP

    To allow large file upload in PHP, you need to edit php.ini file and change fllowing settings

    memory_limit = 512M
upload_max_filesize = 800M
post_max_size = 800M
max_input_time = 6000
max_execution_time = 600

    If you have Dedicated or VPS, you can edit php.ini file using ssh. To find location of this file, upload a phpinfo page to your server, that will display location of php.ini used by your web site.

    Some control panel like CPanel have option to edit php.ini settings.

  • Reverse proxy

    Reverse proxy sit in front of a web server. All traffic come to reverse proxy, then reverse proxy route traffic to one or more backend web servers.

    Nginx and Vranish are popular software used as reverse proxy.

    Show Real IP

  • ArchLinux

    ArchLinux Package Management with pacman
    Install netdata on ArchLinux
    Install iperf3 on ArchLinux
    Install nslookup on ArchLinux

  • ArchLinux Package Management with pacman

    To update packages, run

    pacman -Syu

    To install a software, run

    pacman -S PKG_NAME

    To search for a package

    pacman -Ss PKG_NAME

    Show information about a specific package

    pacman -Si PKG_NAME

    To get list of all files installed by a package

    pacman -Fl PKG_NAME
pacman -Ql PKG_NAME

    To verify presence of all files installed by a package

    pacman -Qk PKG_NAME

    To find which package provide a file

    pacman -Fsy FILE_NAME

    Example

    [root@PAR-139278 ~]# pacman -Fsy apachectl
:: Synchronizing package databases...
 core is up to date
 extra is up to date
 community is up to date
extra/apache 2.4.39-1
    usr/bin/apachectl
[root@PAR-139278 ~]#

  • Online Movie Website

    Here are some sites to Watch Online Movies for free.

    https://sdarot-il.ml/new/ – Powered by vShare youtube clone script.

    https://openloadmovies.net/

    https://watch.plex.tv/

  • Install ruby from source

    Install ruby from source

    Ruby Programming

    Download latest version of ruby source code from

    https://www.ruby-lang.org/en/downloads/

    At the time of writing this, latest version is 2.6.0

    cd /usr/local/src
wget https://cache.ruby-lang.org/pub/ruby/2.6/ruby-2.6.0.tar.gz
tar -zxvf ruby-2.6.0.tar.gz
cd ruby-2.6.0
./configure
make
make install

  • apt – Problem unlinking the file auxfiles

    When i get apt update on a Debian 9 server, i get following error

    # apt update
Get:1 http://ftp.debian.org/debian stretch-updates InRelease [91.0 kB]
Hit:2 http://security.debian.org stretch/updates InRelease                                                                          
Hit:3 https://packages.sury.org/php stretch InRelease                              
Ign:4 http://ftp.us.debian.org/debian stable InRelease                             
Hit:5 http://ftp.us.debian.org/debian stable Release
Fetched 91.0 kB in 0s (165 kB/s)
Reading package lists... Done
Building dependency tree       
Reading state information... Done
All packages are up to date.
W: Problem unlinking the file auxfiles - Clean (21: Is a directory)
#

    The problem is fixed by deleting

    rm -rf /var/lib/apt/lists/
  • Install Redis from Source

    Install Redis from Source

    To install Redis from the source, run

    cd /usr/local/src
wget http://download.redis.io/redis-stable.tar.gz
tar xvzf redis-stable.tar.gz
cd redis-stable
make
make install

    Copy config file

    mkdir /etc/redis/
cp /usr/local/src/redis-stable/redis.conf  /etc/redis/

    Create redis user

    groupadd -r redis
useradd -r -g redis -s /sbin/nologin -d /var/lib/redis -c "redis Daemons" redis

    Create directory

    mkdir /var/lib/redis
chown redis:redis /var/lib/redis
chmod 770 /var/lib/redis

    Set data directory

    vi /etc/redis/redis.conf

    Find

    dir ./

    Replace with

    dir /var/lib/redis

    Create service file

    vi /usr/lib/systemd/system/redis.service

    Add the following content to the file

    [Unit]
Description=Redis persistent key-value database
After=syslog.target

[Service]
ExecStart=/usr/local/bin/redis-server /etc/redis/redis.conf
RestartSec=5s
Restart=on-success
User=redis
Group=redis

[Install]
WantedBy=multi-user.target

    Enable and start Redis

    systemctl enable redis
systemctl start redis

    To find Redis version, run

    redis-server --version

    To monitor Redis, you can use redis-cli

    Back to redis

  • Find Disk Usage in Linux

    du command shows disk usage.

    du -h --max-depth=1

    If you want to sort the result, see How to sort the result of du -h command

    To see disk usage on the current partition only, run

    du -hx --max-depth=1

    To sort by disk space

    du -k --max-depth=1 | sort -n

    To display the top 20 largest folders/files

    du -ahx . | sort -rh | head -20
du -h | sort -hr | head -n  30