Common Bash commands and a few handy tricks

Basics

• Navigation

  cd .. # go up one
  cd ~ # go to home
  pwd # current folder
  ls # list files, -a hidden, -l more info, -R recursive
  

• File management

  mv a.txt b.txt # rename to b.txt
  mv a.txt ../other/folder/ # move
  cp a.txt a-copy.txt # copy
  mkdir new_directory # create new directory
  touch file.py # create new file
  rm oldfile.txt # remove file
  rm -r full_folder/ # delete folder and its contents
  

File Editor / Vim

i # invoke Insert mode for editing
o # append a new line after current line and invoke Insert mode
cc # clear current line and invoke Insert mode
u # undo
ESC # stop editing and return to Command mode
/search # searches for the regex pattern, in this case 'search'
n # next search result
:w # save
:wq # save and quit
:q # quit
:q! # quit without saving

History

cd - # go back a directory
history # view all commands
!! # last command
<Up key> # last command

Also, <Ctrl-R> then type to search history. <Ctrl-R> to cycle through results, <Enter> to execute.

Process Management

command1 ; command2 # run command2 after command1
command1 && command2 # run command2 if command1 succeeds
command1 || command2 # run command2 if command1 fails
command1 & command2 # run at same time
ps -e # show all processes
command & # run in background
kill 1234 # kills process by pid
killall python # kill by name
kill -9 1234 # force kill

Searching/finding

• Grep
  • can be used to filter a command by keyword eg history or ps -e
  • can also search contents of files:

      grep -r nav ./layouts/ # searches all items in layouts folder for 'nav'
      grep -lr nav . # lists names
      grep -ir Nav . # ignore case
      grep -er '(http|ftp)s?:' # regex
    

• Find

  find . -name *.py # find all files in this dir with .py extension
  find . -iname Bill.py # ignore case
  find . -mtime 7 -iname readme # finds any file with 'readme' in the name modified in the last 7 days
  

Misc Tricks

• Autocomplete
  • once to autocomplete a filename.
  • twice to view all options
• Piping

  history | grep python # runs history command but filtered on 'python'
  

• Variables

  NAME="ghan"
  echo "Hi $GHAN"
  env # show all vars