中国DOS联盟论坛

中国DOS联盟

-- 联合DOS 推动DOS 发展DOS --
联盟域名:www.cn-dos.net 论坛域名:www.cn-dos.net/forum
游客 | 登录 | 注册 | 会员 | 搜索 | 中国DOS联盟
中国DOS联盟论坛
现在时间是 2026-08-08 09:50
47,811 主题排行 / 349,895 发帖 / 今日 0 篇 / 48,253 会员排行
DOS批处理 & 脚本技术(批处理室) » 【共享】文件 网络 系统 批函数若干
可打印版本  2,464 / 16
第16楼 plp626 发表于 2008-04-27 03:06
银牌会员 发帖 1,020 积分 2,278
Reading Files
This page shows how to read specific lines from a text file. There are many ways to have the for /f command read the input file, for instance:-

for /f "delims=" %%a in (input.txt) do ...

for /f "delims=" %%a in ('type input.txt') do ...

for /f "delims=" %%a in ('more ^< input.txt') do ...

However, only the last method (using the more command) will give consistent results across Windows NT, 2000, XP and 2003. The first method does not recognise unicode files. Also, the usebackq switch must be used if the input filename contains spaces. The second method, using the type command, also fails to recognise unicode files on Windows 2000, XP and 2003 if the input file does not begin with a bit order mark (BOM).

In all the examples, assume the contents of of the file numbers.txt to be:-

one
two
three
four
five
six
seven
eight
nine
ten

Displaying the first line

This example prints one.

@echo off & setlocal ENABLEEXTENSIONS
set "first="
for /f "delims=" %%a in ('more ^< numbers.txt') do (
if not defined first set first=%%a
)
echo/%first%

Displaying the first X lines

This example prints one, two and three.

@echo off & setlocal ENABLEEXTENSIONS
set "lines=3"
set i=-1
set "ok="
for /f "delims=" %%a in ('more ^< numbers.txt') do (
set/a i+=1 & for /f %%z in ('echo/%%i%%') do (
if "%%z"=="%lines%" set ok=1
)
if not defined ok echo/%%a
)

Displaying the last line

This example prints ten.

@echo off & setlocal ENABLEEXTENSIONS
for /f "delims=" %%a in ('more ^< numbers.txt') do set "last=%%a"
echo/%last%

Displaying the last X lines

This example prints nine and ten.

@echo off & setlocal ENABLEEXTENSIONS
set "lines=2"
for /f %%a in ('find/c /v "" ^< numbers.txt') do set/a skip=%%a-lines
for /f "delims=" %%a in ('more/e +%skip% ^< numbers.txt') do (
echo/%%a
)

Displaying the Nth line

This example prints three. Note that instead of using the more command's /e switch, the skip option could have been used with the for /f command, however, this fails is it is set to any number less than one.

@echo off & setlocal ENABLEEXTENSIONS
set LineNo=3
set "line="
set/a LineNo-=1
for /f "delims=" %%a in ('more/e +%LineNo% ^< numbers.txt') do (
if not defined line set "line=%%a"
)
echo/%line%

Displaying the Nth line plus X number of lines

This example prints five and six.

@echo off & setlocal ENABLEEXTENSIONS
set start=5
set "lines=2"
set/a i=-1,start-=1
set "ok="
for /f "delims=" %%a in ('more/e +%start% ^< numbers.txt') do (
set/a i+=1 & for /f %%z in ('echo/%%i%%') do (
if "%%z"=="%lines%" set ok=1
)
if not defined ok echo/%%a
)
第17楼 learner0 发表于 2008-04-27 11:21
初级用户 发帖 49 积分 108
顶一下,收藏..
上一页  1 2
[ 联系联盟系统管理团队 - 中国DOS联盟 - 标准版 ]
Sponsored by ifanr Inc | © 2001–2023