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

1、 Yes num.txt Sort , And output the results to sorted_num.txt in

[[email protected] ~]# sort num.txt > sorted_num.txt
[[email protected] ~]# more num.txt 
1
3
5
2
4
[[email protected] ~]# more sorted_num.txt 
1
2
3
4
5

2、 Yes args.txt Sort , And output the results to sorted_args.txt in

[[email protected] ~]# sort args.txt > sorted_args.txt
[[email protected] ~]# more sorted_args.txt 
args1
args2
args3
args4
args4
test

3、 Yes num.txt and args.txt Sort , And output the results to sorted_merge.txt in

[[email protected] ~]# sort num.txt args.txt > sorted_merge.txt
[[email protected] ~]# more sorted_merge.txt 
1
2
3
4
5
args1
args2
args3
args4
args4
test

4、 Yes args.txt After sorting, de re output

[[email protected] ~]# sort -u args.txt 
args1
args2
args3
args4
test

5、 Merge sorted_args.txt and sorted_num.txt And output

[[email protected] ~]# cat sorted_args.txt sorted_num.txt 
args1
args2
args3
args4
args4
test
1
2
3
4
5

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

[[email protected] ~]# sort -k 2 info_txt 
2 li  80
No Name    Score
4 sun  60
3 wang 90
1 zhang 20

tr command

tr Instruction reads data from standard input , After replacement or deletion , Output the results to standard output .
grammar ： tr [OPTION]…SET1[SET2]
Parameter description ：
-c Invert set character . That is to say, it conforms to SET1 Don't deal with the part of , The rest of the non conformity is converted
-d Delete instruction characters
-s Reduce the number of consecutive characters to a specified single character

List ：
1、 take 26 After a lowercase letter 13 Replace the first letter with a capital letter

[[email protected] ~]# echo qwertyuiopasdfghjklzxcvbnm | tr j-z J-Z
QWeRTYUiOPaSdfghJKLZXcVbNM

2、 take hello 123 world 456 Replace the numbers in with empty characters

[[email protected] ~]# echo 'hello 123 world 456' | tr 0-9 ' '
hello     world    
[[email protected] ~]# echo 'hello 123 world 456' | tr -s 0-9 ' '
hello world 
[[email protected] ~]# echo 'hello 123 world 456' | tr -d 0-9 
hello  world 

3、 take hello 123 world 456 Replace letters and spaces in , Just keep the numbers

[[email protected] ~]# echo 'hello 123 world 456' | tr -cd 0-9 
123456