shell中一行行读取文件非常简单

while read -r line; do COMMAND; done < input.file

这里-r参数是为了避免反斜线\

更为完善且清晰的脚本

#!/bin/bash
input="/path/to/txt/file"
while IFS= read -r var
do
  echo "$var"
done < "$input"

• 案例

#!/bin/bash
file="/home/vivek/data.txt"
while IFS= read -r line
do
        # display $line or do somthing with $line
    printf '%s\n' "$line"
done <"$file"

• 如果要按照列来读取

#!/bin/bash
file="/etc/passwd"
while IFS=: read -r f1 f2 f3 f4 f5 f6 f7
do
        # display fields using f1, f2,..,f7
        printf 'Username: %s, Shell: %s, Home Dir: %s\n' "$f1" "$f7" "$f6"
done <"$file"

参考

• Linux/UNIX: Bash Read a File Line By Line