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
)

Originally posted by bagpipe at 2006-7-3 10:21 AM:
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 . ...

Originally posted by namejm at 2006-7-27 05:51:
　　more的用法真是强。以后要显示指定行的内容就有模式可套用了，呵呵，不错不错。

这一页告诉大家如何从一个文本文件读取某一行. 这里有很多方法可以使用 for/f 读取 input.txt 的内容,例如:



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 ... 



不过，只有最后一种方法(使用 more 命令) 可以在不同的操作系统中如：Windows NT, 2000, XP and 2003 取得一致的结果。第一种方法不能识别UNICODE编码文件，并且, 如果输入文件名包含空格，usebackq 参数必须被使用，第二个方法, 使用 type 命令, 在 windows2000, XP 和 2003 中如果文件不是从字节序标记(BOM)开始 ，同样不识别unicode 文件。



在所有例子中,假设numbers.txt的内容为：



one

two

three

four

five

six

seven

eight

nine

ten



显示第一行



这个例子输出 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%



显示前几行



这个例子输出 one, two 和 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

)



显示最后一行



这个例子输出 ten。



@echo off & setlocal ENABLEEXTENSIONS

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

echo/%last%



显示最后几行



这个例子输出 nine 和 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

)



显示第 n 行



这个例子输出three，注意这里使用more的 /e 参数 来跳过指定的行数，配合for/f 使用，当数值小于1时会失败。





@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%



显示第 n 行加上 X 行



这个例子输出five和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

)