📈 Beyond Basics: Using Advanced Linux 🐧 Commands

👉 Quick Intro 🔥

In this blog, I will explain advanced commands related to:-

1. Searching files

2. Text editor

3. File compression and archiving commands

4. Redirection

5. Environment variables

👉 Search Files 🔍

• To search files there are two commands find & locate

• find is most commonly used, because it gives the latest data

• locate a bit faster than find, because it searches in locate DB only not the entire file system, locate DB has to be synced with the file system after every change to get the latest data. [so it is avoided]

  find <path> -name <file> --> Search file in given path using file name & return path of file, if file exists

  

  find <path> -name <pattern> --> Search file in given path using pattern & return path of a file, if file exists

  

  \==> If you see above image, we can search file by extension or starting file name

  find <path> -empty --> Search empty files or directories in the given path

  

  find <path> -perm XXX --> Search files or directories that match given permission

  

  find <path> -type <d/f> --> Search files by type files or directories

  

  NOTE:- You can combine different flags based on requirement

  find <path> <other-flags> -exec <command> {} \; --> Execute some command on the output of the other flags used

  

  

  

👉 Text Editor 📝

• There are two most used editors vi and sed

1. Vi editor

   vi file --> Open file in the editor [create a new file if doesn't exist]

   vi -r file --> Open file in read-only mod

   • There are two modes in vi editor

     🔴 Command mode

   • vi editor is opened in command mode by default

   • This mode allows us to use shortcuts

     dd --> Delete line where cursor is present

     d<n> --> Delete next n+1 lines including line where cursor is present

     u --> undo

     k --> move up by one line

     j --> move down by one line

     l --> move right by one character

     h --> move left by one character

     $ --> positions cursor to end of line

     0 --> positions cursor to beginning of line

     <n>G --> go to nth line

     w --> positions cursor to next word first letter

     b --> positions cursor to previous word first letter

     ( --> positions cursor to start of file

     ) --> positions cursor to end of file

     /word --> search for word [n for next search, N for previous search]

🔴 Insert mode

• To get into command mode from insert mode press Esc

  :wq --> save and exit file

  :q --> exit file without doing change

  :q! --> exist file without saving changes

  :n --> position cursor to nth line

1. Stream editor

   It shows updated on terminal only, wont update source file by default

   

   sed 's/old/new/' <file> --> display output by changing only first occurrence of word in each line

   

   sed 's/old/new/n' <file> --> display output by changing nth occurrence of word in each line

   

   sed 's/old/new/g' <file> : display output by changing all occurrences of word in each line

   

   sed '<n>d' <file> : display output by deleting nth line

   

   sed '$d' <file> : display output by deleting last line

   

   sed '<x>,<y>d' <file> : display output by deleting lines between [x,y]

   

   Note :- all the changes are not saved by default, you need to use -i after sed to save changes

👉 File Compression and Archiving 🗃️

• Archiving files is all about combining multiple files and directories into a single file, for easier portability and storage [size doesn't change]

• Compressing files means it reduces the size of files and directories by removing unnecessary things and bundling in a single file

• There are two commands that are used most tar and zip to archive and compress files

  🚩FLAGS

  c --> Create a new archive file

  x --> Extract archive file

  v --> Verbose

  f --> Specify file name

  z --> gzip compression [.tar.gz]

  tar cvf <output> <files-to-be-archived> --> Archive files into a single file

  

  tar xvf <output> <files-to-be-archived> --> Extract files from the archive file

  

  tar tvf <tar-file> --> View files in tar file with details same as in ls -l

  

  tar cvfz <output>.tar.gz <files-to-be-compressed> --> Archive and compress files using gzip compression, it will create .tar.gz output compressed file

  

  tar xvfz <output>.tar.gz --> Extract compressed file using gzip compression

  

  \==> zip is not an in-built command, need to install it sudo apt-get install zip

  zip <output-file>.zip <files-to-be-compressed> --> Compress multiple files into a single file

  

  🚩 FLAGS

  -d --> Remove file from zip file

  -u --> Replace file with updated one in the zip file or add a new file

  -x --> Exclude files that are to be skipped during compression

  -r --> Include all files and sub-directories

  -m --> After zipping, delete the directory or file

  

  

  

  unzip <zip-file> --> Unzip files from .zip file

  

  unzip -l <zip-file> --> Display files in .zip file

  

👉 Redirection ↪️

👉 Environment Variables ✅

• Environment variables are used to store configuration settings, system information, & other variables that can be accessed by processes and shell scripts.

• Already existing environment variables can be seen using env or printenv

  

  export VAR=Value --> Create a new environment variable [will last only till logout]

  echo $VAR --> Print value of environment variable

  unset VAR --> Remove environment variable

  

  export -p --> show all exported environment variables

  

  Happy Learning!!! 👋