Bash Commands You Should Know

bash.md

Bash Commands You Should Know

File System

Concepts

Full Paths

• Begin with /
• Examples
  • /full/path/to/file
  • /home/kim/dev/hello-world.txt

Relative Paths

• Do not begin with a /
• Reference files or directories relative to the current directory
• Examples
  • relative/path/to/file
  • ../relative/path/to/file - ../ - Reference the parent directory
  • ../../../relative/path/to/file - Reference the parent of the parent of the parent directory

Current Directory

• . references the current directory
• Examples
  • ./some-file - Reference the file some-file in the current directory
  • ls . - List the files in the current directory

Parent Directories

• ../ references the parent directory
• You can use multiples (../../../) to reference a directory multiple levels above
• Examples
  • ../some-file - Reference the file some-file which exists one directory above the current directory
  • ls ../../../ - List the contents of the directory three levels above the current directory

Commands

cd [path_to_directory]

• What does it do?
  • Change directory
• Examples
  • cd - Change to home directory
  • cd /full/path/to/dir - Change to the specified directory
  • cd relative/path/to/dir
  • cd .. - Change to parent directory
  • cd ../../../relative/path/to/dir - Change to specified directory, with each ../ indicating a parent directory

ls [path_to_directory]

• What does it do?
  • List the contents of a directory
  • Does not inherently list hidden files
• Examples
  • ls - List contents of current directory
  • ls /full/path/to/dir - List contents of specified directory
  • ls relative/path/to/dir
  • ls -la - List all contents of current directory (including hidden files) along with permission and ownership details

mkdir <path_to_new_directory>

• What does it do?
  • Create a new directory
• Examples
  • mkdir new-dir-name - Make a new directory in current directory
  • mkdir /full/path/to/new/dir - Make a new directory at the specified location
  • mkdir relative/path/to/new/dir

pwd

• What does it do?
  • Print full path to the current directory

rm <path_to_file>

• What does it do?
  • Remove a file
  • Note - rm permanently deletes files without sending them to trash first, so be careful!
• Examples
  • rm /full/path/to/file - Remove specified file
  • rm relative/path/to/file
  • rm ../../../relative/path/to/file
  • rm -r /full/path/to/dir - Remove specified directory and all of its contents (files and subdirectories)
  • rm -r relative/path/to/dir

touch <path_to_file>

• What does it do?
  • Create a new file
• Examples
  • touch new-file-name - Create a new file in current directory
  • touch /full/path/to/new/file - Create a new file at the specified location
  • touch relative/path/to/new/file
  • touch ../../../relative/path/to/new/file

Other Concepts and Commands

• grep
• echo
• which
• Subshells and $()
• Permissions and chmod
• Ownership and chown
• Parameter expansion
• Shell variables
• Conditionals and test
• $PATH
• ~/.bash_profile
• source
• export
• PYTHONPATH