The fourth job: about the usage of cat, grep, cut, sort, uniq, VIM, TR and other commands

Homework today ：
1. File content browsing
  a.cat see /etc/passwd The contents of the document , And output with line number
  b. Use more/less see /etc/passwd Content , And each page displays 10 That's ok
  c. Use head/tail Before viewing the files separately 5 Line content and after 5 Row content
  d. Use grep see /etc/passwd neutralization root Related content

2.cut Command to use ：
  Given the file cut_data.txt And the content is ：
  No Name    Score
  1 zhang 20
  2 li  80
  3 wang 90
  4 sun  60
  Use the default delimiter to cut the contents of the file , And output the first field after cutting
      Cut file content , And output the first field and the third field after cutting
  Cut by byte ： Output the first byte to the second byte of the cut 10 Bytes of content
  Cut by character ： Output the first character and the second character after cutting 5 The content of a character
  Cut according to the specified delimiter ： The contents are as follows , Output the contents of the first field and the third field
  No|Name|Score
  1|zhang|20
  2|li|80
  3|wang|90
  4|sun|60
3.uniq Command to use ： New file uniq_data.txt, The content of the document is
     Welcome to Linux
     Windows
     Windows
     Mac
     Mac
     Linux
     
    Use uniq The command outputs the result after de duplication
    Use uniqmingl Output only duplicate lines
    Use uniq The command outputs non repeating lines
    Use uniq The command counts the number of repetitions
4.sort command ： Given the file num.txt, args.txt
      The contents of the document :num.txt
         1
      3
      5
      2
      4
    The contents of the document :args.txt
     test
     args1
     args2
     args4
     args4
     args3
    Yes num.txt Sort , And output the results to sorted_num.txt in
    Yes args.txt Sort , And output the results to sorted_args.txt in
    Yes num.txt and args.txt Sort , And output the results to sorted_merge.txt in
    Yes args.txt After sorting, de re output
    Merge sorted_args.txt and sorted_num.txt And output  
    Given the file info_txt： Press the second column as key Sort
    No Name    Score
    1 zhang 20
    2 li  80
    3 wang 90
    4 sun  60
5. take 26 After a lowercase letter 13 Replace the first letter with a capital letter
    take hello 123 world 456 Replace the numbers in with empty characters
    take hello 123 world 456 Replace letters and spaces in , Just keep the numbers