如何在 Bash 脚本中逐行读取文件？
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How to read file line by line in Bash script?
提问by voyvoda
I have a problem with reading a file line by line with bash script. Here is the script:
我在使用 bash 脚本逐行读取文件时遇到问题。这是脚本：
#!/bin/bash
file="cam.txt"
while IFS=: read -r xf1 xf2 xf3
do
printf 'Loop: %s %s %s\n' "$xf1" "$xf2" "$xf3"
f1=$xf1
f2=$xf2
f3=$xf3
done < $file
printf 'After: %s %s %s\n' "$f1" "$f2" "$f3"
Here is cam.txt:
这是cam.txt：
192.168.0.159
554
554
Here is the output:
这是输出：
Loop: 192.168.0.159
Loop: 554
Loop: 554
After: 554
What could be the problem?
可能是什么问题呢？
采纳答案by Lukas Isselb?cher
Your code leads me to believe you want each line in one variable.
你的代码让我相信你希望每一行都在一个变量中。
Try this script (I know this can be done easier and prettier, but this is a simple and readable example):
试试这个脚本（我知道这可以更容易、更漂亮，但这是一个简单易读的例子）：
#!/bin/bash
file="cam.txt"
while read -r line
do
printf 'Line: %s\n' "$line"
current=$line
last=$current
secondlast=$last
printf 'Loop: %s %s %s\n' "$current" "$last" "$secondlast"
done < $file
printf 'After: %s %s %s\n' "$current" "$last" "$secondlast"
Simpler version:
更简单的版本：
{ read -r first; read -r second; read -r third; } <cam.txt
printf 'After: %s %s %s\n' "$first" "$second" "$third"
