Shell 逐行读取单个文件或者多个文件内容

[root@zt94886 ~]# less 1.txt
asdc
sadca

asdc
方式1：while循环逐行读取文件内容
#!/bin/bash
cat ./1.txt | while read line; do
echo $line
done
方式2：while循环逐行读取文件内容
#!/bin/bash
while read LINE; do
echo $line
done < ./1.txt
执行结果：
[root@zt94886 ~]# sh 1.sh
asdc
sadca

asdc

方式3：for循环批量读取多个文件内容：
[root@zt94886 /script/day/var]# ls
1.txt 2.txt 3.txt
[root@zt94886 /script/day/var]# pwd
/script/day/var

[root@zt94886 ~]# less /script/day/var/1.txt
asdcasd
asdcasdc
asdcasdc
asdcasdc
asdcasdc
asdcasdc
asdcasdc

[root@zt94886 ~]# less /script/day/var/2.txt
12123
123123
123123

[root@zt94886 ~]# less /script/day/var/3.txt
asdc asdc
sadcasdc
asdcasdc asdcasdc asdcawdc

asdc
asdcasdcasdc

asdcasdcasdc

asdcasdcasdc

#!/usr/bin/bash
cd /script/day/var/
for i in $(ls *)
do
cat $i | while read line
do
echo $line
done

done

执行结果：
[root@zt94886 ~]# sh for.sh
asdcasd
asdcasdc
asdcasdc
asdcasdc
asdcasdc
asdcasdc
asdcasdc

12123
123123
123123

asdc asdc
sadcasdc
asdcasdc asdcasdc asdcawdc

asdc
asdcasdcasdc

asdcasdcasdc

asdcasdcasdc

注意：使用For循环逐行读取文件时，For循环取值列表是以空白符或者TAB分割，针对空行，For循环会忽略，而While循环，针对空行还会输出。初学Shell,难免有错误之处，欢迎指正！