Linux articles

Vim is the most popular Linux text editor, it was created in 1978 and is used to present days.

Vim has two modes: “Command mode” where you can insert many commands, and “Insert mode” – where you can insert and edit text document. By default Vim open all documents in “Command mode”, to enter into the “Insert mode” – press button “i“.

The most asked question is – “How to exit Vim?” – it is very simple – in Command mode enter :q! and press Enter. This command exit Vim without saving any changes.

:q!

To save file – enter command :w <filename> and press Enter:

:w file.txt

To save file and exit Vim use command :wq and press Enter

:wq

You just need to write in terminal command:

wine uninstaller

This command will start an Add/Remove applet similar to what you get in Windows, which will list your installed WINE programs.

Select program and press button “Uninstall”.

It was very simple 😉

To set default browser in Debian or Ubuntu open terminal and write command:

sudo update-alternatives --config x-www-browser

As you can see, we have four alternatives of browsers, installed in operating system, just enter number of browser and press Enter.

There are there types of file permissions in Linux:

1. Owner permissions
2. Group permissions
3. Other permissions

Also you can set permissions for read, write and execute file for this three groups.

To set correct permissions for all files and folders in currend folder use command:

find . -type f -print0 | xargs -0 chmod 644
find . -type d -print0 | xargs -0 chmod 750

This commands will grant readm write, execute access for owner, read access for group and block all access for other users.

If you wand to grant access to files and folders for other users use commands:

find . -type f -print0 | xargs -0 chmod 665
find . -type d -print0 | xargs -0 chmod 751

To install GPG on your Debian/Ubuntu/Mint Linux operating system use command:

sudo apt install gpg

Simple encrypt command with password:

gpg -c [FileName.txt]

Simple decrypt encrypted file with gpg:

gpg -o [FileName.txt] -d [FileName.txt.gpg]

This command decrypt enctypted file FileName.txt.gpg into normal file FileName.txt

Encryption using a key pair (asymmetric encryption):

Default GPG folder is: /home/user/.gnupg. Generate private and public keys:

gpg --full-generate-key

Answer the several questions (encryption type: RSA, keysize: 4096 for better encryption, key expiration time, your name and email address) and press “O” if all changes are correct.

To view public keys use command:

gpg -k

To view secret gpg keys use command:

gpg -K

To run Windows programs in Linux we use Wine. But how to open any file with exe program using Wine? For example we have 1.txt file. To run this file with notepad.exe use command:

wine "/home/user/notepad.exe" 1.txt

To associate some type of files with EXE program we can use shell script:

#!/bin/sh

QUICKPARLOCATION="/home/user/Notepad.exe"
PARAM=`winepath -w "$*" 2>/dev/null`
wine "$QUICKPARLOCATION" "$PARAM" &
exit 0

Put this file in /home/user/bin directory. Open file properties and in field “Open with” select Notepad.sh script:

Sometimes if server is shutdown incorrect filesystem filesystem can be corrupted and loaded in “read only” mode.

To check file system status use command:

mount | grep /dev/sd

This command show filesystem status, if filesystem is read only – you will see “ro” status: /dev/sda2 on / type ext4 (ro,readonly,data=ordered)

To fix filesystem use command:

fsck /dev/sda2

This command will fix all errors on filesystem, To apply fix enter y on keybord. When fixing is complete reboot system and check filesystem again.