How to split large text file in windows?

Question

I have a log file with size of 2.5 GB. Is there any way to split this file into smaller files using windows command prompt?

Answer 1

If you have installed Git for Windows, you should have Git Bash installed, since that comes with Git.

Use the split command in Git Bash to split a file:

• into files of size 500MB each: split myLargeFile.txt -b 500m

• into files with 10000 lines each: split myLargeFile.txt -l 10000

Tips:

• If you don't have Git/Git Bash, download at https://git-scm.com/download

• If you lost the shortcut to Git Bash, you can run it using C:\Program Files\Git\git-bash.exe

That's it!

---

I always like examples though...

Example:

You can see in this image that the files generated by split are named xaa, xab, xac, etc.

These names are made up of a prefix and a suffix, which you can specify. Since I didn't specify what I want the prefix or suffix to look like, the prefix defaulted to x, and the suffix defaulted to a two-character alphabetical enumeration.

Another Example:

This example demonstrates

• using a filename prefix of MySlice (instead of the default x),
• the -d flag for using numerical suffixes (instead of aa, ab, ac, etc...),
• and the option -a 5 to tell it I want the suffixes to be 5 digits long:

Answer 2

Set Arg = WScript.Arguments
set WshShell = createObject("Wscript.Shell")
Set Inp = WScript.Stdin
Set Outp = Wscript.Stdout
    Set rs = CreateObject("ADODB.Recordset")
    With rs
        .Fields.Append "LineNumber", 4 

        .Fields.Append "Txt", 201, 5000 
        .Open
        LineCount = 0
        Do Until Inp.AtEndOfStream
            LineCount = LineCount + 1
            .AddNew
            .Fields("LineNumber").value = LineCount
            .Fields("Txt").value = Inp.readline
            .UpDate
        Loop

        .Sort = "LineNumber ASC"

        If LCase(Arg(1)) = "t" then
            If LCase(Arg(2)) = "i" then
                .filter = "LineNumber < " & LCase(Arg(3)) + 1
            ElseIf LCase(Arg(2)) = "x" then
                .filter = "LineNumber > " & LCase(Arg(3))
            End If
        ElseIf LCase(Arg(1)) = "b" then
            If LCase(Arg(2)) = "i" then
                .filter = "LineNumber > " & LineCount - LCase(Arg(3))
            ElseIf LCase(Arg(2)) = "x" then
                .filter = "LineNumber < " & LineCount - LCase(Arg(3)) + 1
            End If
        End If

        Do While not .EOF
            Outp.writeline .Fields("Txt").Value

            .MoveNext
        Loop
    End With

Cut

filter cut {t|b} {i|x} NumOfLines

Cuts the number of lines from the top or bottom of file.

t - top of the file
b - bottom of the file
i - include n lines
x - exclude n lines

Example

cscript /nologo filter.vbs cut t i 5 < "%systemroot%\win.ini"

Another way This outputs lines 5001+, adapt for your use. This uses almost no memory.

Do Until Inp.AtEndOfStream
         Count = Count + 1
         If count > 5000 then
            OutP.WriteLine Inp.Readline
         End If
Loop

Answer 3

Below code split file every 500

@echo off
setlocal ENABLEDELAYEDEXPANSION
REM Edit this value to change the name of the file that needs splitting. Include the extension.
SET BFN=upload.txt
REM Edit this value to change the number of lines per file.
SET LPF=15000
REM Edit this value to change the name of each short file. It will be followed by a number indicating where it is in the list.
SET SFN=SplitFile

REM Do not change beyond this line.

SET SFX=%BFN:~-3%

SET /A LineNum=0
SET /A FileNum=1

For /F "delims==" %%l in (%BFN%) Do (
SET /A LineNum+=1

echo %%l >> %SFN%!FileNum!.%SFX%

if !LineNum! EQU !LPF! (
SET /A LineNum=0
SET /A FileNum+=1
)

)
endlocal
Pause

See below: https://forums.techguy.org/threads/solved-split-a-100000-line-csv-into-5000-line-csv-files-with-dos-batch.1023949/

Answer 4

Of course there is! Win CMD can do a lot more than just split text files :)

Split a text file into separate files of 'max' lines each:

Split text file (max lines each):
: Initialize
set input=file.txt
set max=10000

set /a line=1 >nul
set /a file=1 >nul
set out=!file!_%input%
set /a max+=1 >nul

echo Number of lines in %input%:
find /c /v "" < %input%

: Split file
for /f "tokens=* delims=[" %i in ('type "%input%" ^| find /v /n ""') do (

if !line!==%max% (
set /a line=1 >nul
set /a file+=1 >nul
set out=!file!_%input%
echo Writing file: !out!
)

REM Write next file
set a=%i
set a=!a:*]=]!
echo:!a:~1!>>out!
set /a line+=1 >nul
)

If above code hangs or crashes, this example code splits files faster (by writing data to intermediate files instead of keeping everything in memory):

eg. To split a file with 7,600 lines into smaller files of maximum 3000 lines.

1. Generate regexp string/pattern files with set command to be fed to /g flag of findstr

list1.txt

\[[0-9]\]
\[[0-9][0-9]\]
\[[0-9][0-9][0-9]\]
\[[0-2][0-9][0-9][0-9]\]

list2.txt

\[[3-5][0-9][0-9][0-9]\]

list3.txt

\[[6-9][0-9][0-9][0-9]\]

2. Split the file into smaller files:

type "%input%" | find /v /n "" | findstr /b /r /g:list1.txt > file1.txt
type "%input%" | find /v /n "" | findstr /b /r /g:list2.txt > file2.txt
type "%input%" | find /v /n "" | findstr /b /r /g:list3.txt > file3.txt

3. remove prefixed line numbers for each file split:
   eg. for the 1st file:

for /f "tokens=* delims=[" %i in ('type "%cd%\file1.txt"') do (
set a=%i
set a=!a:*]=]!
echo:!a:~1!>>file_1.txt)

Notes:
Works with leading whitespace, blank lines & whitespace lines.

Tested on Win 10 x64 CMD, on 4.4GB text file, 5651982 lines.