bash - 在 bash 脚本中写入文件

Question

我是 bash 的新手，但我正在尝试编写一个执行以下操作的 bash 脚本:

write_to_file()
{
 #check if file exists
 # if not create the file
 # else open the file to edit
 # go in a while loop
 # ask input from user 
 # write to the end of the file
 # until user types  ":q"

 }

谁能指出文献，不胜感激谢谢

Answer 1

更新:因为这是一个 bash 问题，你应该先试试这个。 ;)

cat <<':q' >> test.file

要了解发生了什么，请阅读 bash 的 IO redirection , heredoc syntax和 cat命令

---

正如您在上面看到的，有很多方法可以做到这一点。为了解释更多的 bash 命令，我也按照您要求的方式准备了函数:

#!/bin/bash

write_to_file()
{

     # initialize a local var
     local file="test.file"

     # check if file exists. this is not required as echo >> would 
     # would create it any way. but for this example I've added it for you
     # -f checks if a file exists. The ! operator negates the result
     if [ ! -f "$file" ] ; then
         # if not create the file
         touch "$file"
     fi

     # "open the file to edit" ... not required. echo will do

     # go in a while loop
     while true ; do
        # ask input from user. read will store the 
        # line buffered user input in the var $user_input
        # line buffered means that read returns if the user
        # presses return
        read user_input

        # until user types  ":q" ... using the == operator
        if [ "$user_input" = ":q" ] ; then
            return # return from function
        fi

        # write to the end of the file. if the file 
        # not already exists it will be created
        echo "$user_input" >> "$file"
     done
 }

# execute it
write_to_file