learn-bash.txt

Bash commands

- $ echo
- $ say “Hi There”
- $ date
- $ cal
-  $ whoami
- $ pwd
- $ ls-a (List all hidden files)
- $ ls -l 
- $ drwxr-xr-x   6 debnayak  wheel   192 Nov 26  2021 Applications
    - [d][rwx][r-x][r-x]
    - d - directory
    - rwd-read, write execute by debnayak
    - r-x: read, no write, execute by group wheel
    - r-x: read, no write, execute by everyone else
- $ ls Desktop -la
- $ file sometext.tsx
-  $ cd (Take to home)
- $ open file/folder
- $ open . (Open present working directory)
- $ touch filename.ext (create one / modify date of existing one
- $ xdc-open filename (Ubuntu)
- $ mv filename new filename(Rename a file)
- $ mv fileName Target-Folder(move to Target Folder)
- $ mv Target-Folder/fileName . (Move back)
- $ nano filename (Edit a file and write on the terminal)
    - Ctrl + x Y Enter (To save edited file)
- $ cat file.txt (displays content)
- $ cp filename.txt Target-Folder
- $ rm filename.txt
- $ Star
    - $ mv *.txt NewFolder
    - $ mv NewFolder/*.txt .
    - $ rm NewFolder/*
    - $ cp 1* NewFolder
- $ ls -R
- $ rm -R A-Folder
- $ cp -R A-foler B-folder 
- $ mv A-folder B-foler(Move A-folder to B-folder)
- $mv B-folder/B-foler/ . (Move back)
- $ rm -R *data (Removed  folder where name container data)
- $ echo “Some text” > 1.txt (Single redirect)
- $ echo “Hello” > 1.txt (Replace existing text with new text)
- $ echo “Second Line” >> 1.txt (Add to next line)
- $ ls -l > 2.txt (Create a new file 2.txt with result of ls -l)
- $ cat 1.txt 2.txt > 3.txt (Concatenate 1.txt and 2.txt into 3.txt)
- $ls S* (List all start with S
-  PIPE
    - $ ls -l | tail -3 | sort | less
    - $ cat 1.txt | sort | tail -10 > 2.txt
- $ find
    - $ find FoderName/ -name *.txt
    - $ find FolderName/ -type f
    - $ find FolderName/ -type d
- $ grep
    - $ grep so 1.txt // search text "so" in 1.txt
    - $ grep -i so 1.txt // i for case-insentive search
    - $ ls -R | grep .txt
    - $ ls | grep -v t (Everything except t)
    - $ ls | grep -v "\.png$" (Exclude .png files)
- $ AWK
    - $ awk ‘{print}’ 2.txt
    - $ awk ‘{print $1}’ 2.txt 
    - $ awk ‘{print $(NF-1)}’ 2.txt 
    - $ awk 'NR==1;NR==3 {print $0}' 2.txt
    - $ awk 'NR==1,NR==3 {print $0}' 2.txt
    - $ awk '/Deb/ {print }' 2.txt
    - $ awk '/Deb|Gunjan/ {print }' 2.txt
    - $ awk '/1/ {print }' 2.txt 
    - $ awk '$4~/1/ {print }' 2.txt
    - $ awk '$4~/1/ {print $1,$4}' 2.txt
    - $ awk '$1==$2 {print $1,$4}' 2.txt
    - $ awk ' {print $1, length($1)}' 2.txt
    - $ awk 'NR==2 {print $1, length($1)}' 2.txt
- Sudo
    - $ sudo bash
    - $ sudo chown debnayak 1.txt
    - $ sudo chgrp _guest 1.txt
- chmod
    - $ chmod u=rwx 1.txt
    - $ chmod g=r 1.txt
    - $ chmod o=w 1.txt
    - $ chmod +x 1.txt
    - $ chmod -x 1.txt
    - $ chmod -w 1.txt
    - $ ownership of folder
        - $sudo mkdir closet
        - $ sudo mkdir closet/one
        - $ sudo mkdir closet/two
        - $sudo chown -R debnayak closet
    - Variables
        - $ myvar = 100
        - $ echo $myvar
        - $ myvar = “ls -l”
        - $ $myvar
        - $ echo $PATH
        - $ d = $(pwd) / d=`pwd`
        - $ echo $d
        - $ cd $d
    - Read
        - $ read myvar
        - $ read -p “type ur name: “ name
        - $echo $name
        - $ read -sp “Type ur password “ pass
        - $echo $pass
        - $ unset v1 v2
    - Arithmetic
        - $ echo $(( 10+10))
        - $ echo $(( 10**2))