Vim And Linux

My vim dotfile notes! Below are options and commands I personally found useful through experience. Of course, this list is only getting started and will constantly be updated as time goes on.

In ~/.vimrc file:

use set tabstop = 2 to set tabs to 2 spaces.
use set shiftwidth=2 to set shift width or indent amount to 2 spaces.

To indent/un-indent code bock: first select your desired code block using Shift-V. This activates visual mode and selects entire line(s). Use Up or Down arrow to make you selection and then type Shift-> (that is Shift followed by >) to indent and Shift-< to unindent code block.

To comment code block: first type Ctrl-V to select area. Next, type Shift-I to insert character(s) and type // then hit Esc.

To un-comment selection: Type Ctrl-V to select area then type d to delete selected area.

:retab to retab tabs according to tabstop and shiftwidth rules.

:nohl to turn off highlight (usually after you are done searching for some pattern)

/some_string to search for some pattern (use n to go to next occurence)

Type cw to change current word.

Linux commands

Linux find command looks for a file in some directory. For example: find "." -name "callno.h": will look for file named callno.h in current directory and all subdirectories of current directory.

Linux grep command searches for string pattern in file(s). For example: grep -rnw "." -name "thread_exit" will recursively -r search for all occurences of pattern match in directory . (current directory). Because we passed the -r flag, the search space includes all subdirectories of this directory. Ultimately, running this command will search for the use of "thread_exit" and print line number(s) -n of said occurence(s). Importantly, it will make sure that entire pattern matches as given by the use of -w.

For more grep command information read here.

GNU tar is an archiving program designed to store multiple files in a single file (an archive) and to manipulate such files. File compression tools (like gzip and bzip2) compress single files (not groups of files). So, we use tar to group files into one monolithic file and then use a file compression tool like gzip to compress the file and save memory. In Windows, this is equivalent to WinRAR and WinZip. Read more here.

To unpack a tarball (unpacks tar files compressed with gzip as denoted by .tar.gz file extension):

tar -xvzf filename

To make a new tarball fred.tar.gz from a directory fred (creates a .tar.gz file):

tar -cvzf fred.tar.gz fred

tar option parameter meanings:

c create an archive
f filename the name of the archive file
v verbose: tell me what’s going on
x extract from an archive
z put the archive through gzip

Updating system `PATH` variable

On MacOS

In ~/.zprofile add additional paths you would like to be in your system $PATH. Example

export PATH="/usr/local/mysql/bin:$PATH"
export PATH="/usr/local/kafka_2.12-2.5.0/bin:$PATH"

On Linux

Often I have issues setting up environment variables and/or updating path variables. As a general rule, when adding some directory to $PATH it’s good idea not to overwrite previous value, just append desired directory (e.g., $HOME/bin), in your ~/.bashrc add at the end line:

export PATH="/usr/lib/jvm/java-8-openjdk-amd64/jre" (this path is just an example, use whatever you need)

This sets the $PATH permanently for all future bash sessions. To set it permanently, and system wide (all users, all processes) add set variable in /etc/environment:

sudo vim -H /etc/environment

This file only accepts variable assignments like:

VARNAME="my value" (do not use export here)

Vim And Linux

Linux commands

Updating system PATH variable

On MacOS

On Linux

Updating system `PATH` variable