I wanted to know the number of lines in multiple files, so I tried to get it with a command

When I'm coding ...

How big are you guys creating files? How big is the existing file? I want to know the number of lines in each file.

I think there is.

For studying, I decided to get it with a command!

Execution environment

I installed Linux (Ubuntu) on windows10 using WSL and commanded it.

Get row

use wc command As below wc If you describe it as a target file

$ wc *.txt
 13  13  38 t01.txt
 38  33 106 t02.txt
  4   3   7 t03.txt
 21  18  43 t04.txt
 75  33 116 t05Service.txt
 18  16  35 t06Service.txt
148  14 171 t07Service.txt
317 130 516 total

You can get the information of the txt file that exists in the current directory. The acquired information is displayed for each item.

Number of lines Number of words File size (number of bytes))File name
13   13     38                t01.txt
...
...
317 130 516 total here is the total

Since there is a lot of extra information at this rate Get only the number of lines with the -l option

~/work$ wc *.txt -l
 13 t01.txt
 38 t02.txt
  4 t03.txt
 21 t04.txt
 75 t05Service.txt
 18 t06Service.txt
148 t07Service.txt
317 total

It's much easier to see because it's just the number of lines and the file name.

Displayed in line order.

I used the wc command pipe'|' sort command.

$ wc *.txt -l | sort
  4 t03.txt
 13 t01.txt
 18 t06Service.txt
 21 t04.txt
 38 t02.txt
 75 t05Service.txt
148 t07Service.txt
317 total

It was nicely arranged in the order of the number of file lines.

Next, I will try to get only the "*** Service.txt" file.

$  wc *Service.txt -l | sort
 18 t06Service.txt
 75 t05Service.txt
148 t07Service.txt
241 total

Hooray! I was able to get only the number of lines in the service file.

・ ・ ・: Relaxed:

Now display the average!

First, delete the TOTAL line because it is an obstacle.

I used the sed command. This represents the last line when $ is specified in the address part, so d (delete) is executed for it.

$ wc *.txt -l | sort | sed '$d'
  4 t03.txt
 13 t01.txt
 18 t06Service.txt
 21 t04.txt
 38 t02.txt
 75 t05Service.txt
148 t07Service.txt

It has disappeared! Furthermore Use the awk command to display the average.

$ wc *.txt -l | sort | sed '$d' |  awk '{n += $1}{i +=1 }; END{print int(n/i) }'
45

I got the average number of lines "45" from the above command! !! : rolling_eyes:

By the way, what is awk doing? .. ..

Add the number of lines to n for each line to i+1 When all lines are finished, display: Decimal point truncation (n ÷ i)
awk 　　　　　　'{n += $1}　　{i +=1 }; 　　END　　　　　　　{print　 int(n/i) }'

It's like

The options of the wc command are as follows.

-l
Show the number of lines in the file.

-c
Display the number of bytes in the file.

-m
Display the number of characters in the file.

-L
Display the number of bytes in the longest line.

-w
Display the number of words in the file.

I didn't use it, but it seems that you can check the number of files with the following command.

$ ls -1 | wc -l

The option of the ls command is "-1(Number 1)」
The option of the wc command is "l (lowercase letter L)"

reference What if I want to erase only the last line of text?

[Note about awk] (https://qiita.com/SYutaka/items/b6aadfa279c516a3b90b)