Top of one file to the top of another

[john924xps]

Yeah... I've got two files, and I want to be able to just run a batch file in order to transfer the first line of file A to the top of file B, then deleting that line from file A... I'm clear on how to retrieve text from a file, but I'm not sure how to transfer it to the TOP of another file, as well as deleting that relative line in file A.

And how do you copy the last line of a particular file into a variable without using the <file.txt function repeatedly? Are for loops a must in such a situation? Thanks.

[foxidrive]

Use set /p to get line one into a variable.

echo the variable into a new temp file.
TYPE fileB >> newtempfile.
move /y newtempfile fileB


and removing the line from fileA:
find /v "%variable%" <fileA >tempfile
move /y tempfile fileA


To get the last line, use a for in do and set an environment variable to the metavariable. The last line will be in the envar when the forindo completes.

[dbenham]

Reading every line with a FOR loop to get the last line is inefficient, and potentially unacceptably slow for a large file.

FIND /C can be used to quickly count the number of lines and then the FOR /F SKIP option can be used to quickly read the last line.

Code: Select all

@echo off
set "file=test.txt"
for /f %%N in ('type "%file%"^|find /c /v ""') do set /a skip=%%N-1
if %skip% leq 0 (set "skip=") else set "skip=skip^=%skip%^ "
for /f %skip%usebackq^ delims^=^ eol^= %%A in ("%file%") do set "lastLine=%%A"
set lastLine

Dave Benham

[foxidrive]

Reading every line with a FOR loop to get the last line is inefficient, and potentially unacceptably slow for a large file.

True, Dave, for large files. For small files and moderate directory lists it doesn't warrant the added complexity, IMO.