Download the latest apt-rxx.exe from ​http://download.osgeo.org/osgeo4w/release/apt/. If you like rename to apt.exe. Open a CMD shell and:

SET OSGEO4W_ROOT=C:\Osgeo4W
apt setup
apt update
apt install shell

Results

<b>set osgeo4w_root=d:\test-osgeo4w</b><br> <b>apt setup</b><br>

Root dir not found, creating d:/test-osgeo4w<br> creating d:/test-osgeo4w/etc/setup/<br> creating d:/test-osgeo4w/etc/setup//installed.db<br> getting d:/test-osgeo4w/etc/setup//setup.ini<br> ...100%<br>

<b>apt install shell</b><br>

to install:<br>

shell msvcrt<br>

Fetching ​http://download.osgeo.org/osgeo4w/./release/shell/shell-1.0.0-5.tar.bz2<br> <br> ...100% d:/test-osgeo4w/var/cache/setup/http%3a%2f%2fdownload.osgeo.org%2fosgeo4w/./release/shell/shell-1.0.0-5.tar.bz2<br> <br> a01e6dcdc9e2d2c49424585aa3e1b44f shell-1.0.0-5.tar.bz2 - remote<br> a01e6dcdc9e2d2c49424585aa3e1b44f shell-1.0.0-5.tar.bz2 - local<br> <br> Fetching ​http://download.osgeo.org/osgeo4w/./release/msvcrt/msvcrt-1.0.1-2.tar.bz2<br> ...100% d:/test-osgeo4w/var/cache/setup/http%3a%2f%2fdownload.osgeo.org%2fosgeo4w/./release/msvcrt/msvcrt-1.0.1-2.tar.bz2<br> <br> 195c192b98b7333e2d3f9e04717c2eb5 msvcrt-1.0.1-2.tar.bz2 - remote<br> 195c192b98b7333e2d3f9e04717c2eb5 msvcrt-1.0.1-2.tar.bz2 - local<br> installing shell 1.0.0-5<br> <br>

mkdir "C:\ProgramData\Microsoft\Windows\Start Menu\Programs\OSGeo4W"<br> xxmklink "C:\ProgramData\Microsoft\Windows\Start Menu\Programs\OSGeo4W\OSGeo4W.lnk" "d:\test-osgeo4w\OSGeo4W.bat" " " \ "OSGeo for Windows command shell" 1 "d:\test-osgeo4w\OSGeo4W.ico<br> xxmklink "C:\ProgramData\Desktop\OSGeo4W.lnk" "d:\test-osgeo4w\OSGeo4W.bat" " " \ "OSGeo for Windows command shell" 1 "d:\test-osgeo4w\OSGeo4W.ico<br>

Post_install complete, return code 0<br> installing msvcrt 1.0.1-2<br> <br>

"d:\test-osgeo4w\bin\vcredist_x86.exe" /q<br> del "d:\test-osgeo4w\bin\vcredist_x86.exe"<br> textreplace -std -t bin/o4w_env.bat<br>

Post_install complete, return code 0<br> <br>

<b>apt list</b><br>

msvcrt 1.0.1-2<br> shell 1.0.0-5<br>

---

Shell is only a skeleton, there are no applications installed. So to get something actually useful:

>apt available

 Packages available to install (* = already installed)

agg-devel                       mapscript-dev-python
apache                          mapscript-java
apache-manual                   mapscript-python
...snipped >140 package names...
libxdr                          xerces-c
libxml2                         xerces-c-devel
mapfish_framework               zlib

>apt install gdal
...snip...

>gdalinfo --version
GDAL 1.5.4, released 2009/01/07