Text manipulation

• touch - create empty file (e.g. touch file.txt)

  • echo "Hello World" > file.txt - write “Hello World” to file.txt

  • echo "Hello World" >> file.txt - append “Hello World” to file.txt

• tee - read from standard input and write to standard output and files. Convenient to write logs to file and print them to stdout at the same time

  • python script.py | tee log.txt - write output of script.py to log.txt and print it to stdout

  • echo "Hello World" | tee hello.txt - write “Hello World” to hello.txt and print it to stdout

  • echo "Hello World" | tee -a hello.txt - append “Hello World” to hello.txt and print it to stdout

• sed is a stream editor for filtering and transforming text

  • sed 's/old/new/g' <filename> - replace all occurrences of old with new in file s - substitute, g - global

  • sed '/start_pattern/,/end_pattern/d' <filename> - delete a line with start and end pattern use

• tail - output the last part of files

  • tail -n 10 file.txt - output the last 10 lines of file.txt

  • tail -f file.txt - output appended data as the file grows

Vim

Vim is is a highly configurable text editor

Modes in vim:

• Normal mode - for navigating and editing text (default mode). You can switch to normal mode by pressing Esc key

• Insert mode - for inserting text. You can switch to insert mode by pressing i key

• Visual mode - for selecting text. You can switch to visual mode by pressing v key

  • Visual character mode - for selecting characters of text. You can switch to visual character mode by pressing v key

  • Visual line mode - for selecting lines of text. You can switch to visual line mode by pressing V key

  • Visual block mode - for selecting blocks of text. You can switch to visual block mode by pressing Ctrl + v key

• Command mode - for executing commands. You can switch to command mode by pressing : key

• Replace mode - for replacing text. You can switch to replace mode by pressing R key

Commands in vim:

• vim <filename> - open file in vim or create new file if it doesn’t exist

• :q - quit

• :q! - quit without saving

• :w - save

• :wq - save and quit

• :q! - quit without saving

• :help - show help

• i - insert mode. Means that you can type text. Press Esc to exit insert mode

• d - delete line

• :set number - show line numbers

• :set tabstop=4 - set tabstop to 4 spaces (when you press tab it will insert 4 spaces) (default is 8 spaces)

• :set paste - paste text without auto indent

• y - yank (copy) selected text

• x - cut selected text

• p - paste copied text

• u - undo

• Ctrl + r - redo

• / - search for text (e.g. /Hello + Enter - search for Hello)

• n - go to next search result

• N - go to previous search result

• :s/old/new/g - replace all occurrences of old with new in file s - substitute, g - global

• o - insert new line below current line

• dd - delete line