I have described the differences between the old and new free output format, so now I want to mention how to execute the former free version on Debian Stretch using LD_LIBRARY_PATH environment variable to temporarily substitute a different library for this particular execution.
Operating system version.
$ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 9.4 (stretch) Release: 9.4 Codename: stretch
free utility is provided by the procps package.
$ dpkg-query -S /usr/bin/free procps: /usr/bin/free
List available procps and libprocps packages. You can inspect Debian Jessie – procps detail using web-browser.
$ curl --silent http://ftp.us.debian.org/debian/pool/main/p/procps/ | sed -n -e "/_amd64\.deb/ {s/.*<a.*>\(.*\)<\/a>.*/\1/;p}"
libprocps-dev_3.3.12-3_amd64.deb
libprocps-dev_3.3.12-4_amd64.deb
libprocps0-dev_3.3.3-3_amd64.deb
libprocps0_3.3.3-3_amd64.deb
libprocps3-dev_3.3.9-9_amd64.deb
libprocps3_3.3.9-9_amd64.deb
libprocps6_3.3.12-3_amd64.deb
libprocps6_3.3.12-4_amd64.deb
procps_3.3.3-3_amd64.deb
procps_3.3.9-9_amd64.deb
procps_3.3.12-3_amd64.deb
procps_3.3.12-4_amd64.deb
Create a temporary directory and enter it.
$ mkdir jessie-free
$ cd jessie-free
Create packages directory.
jessie-free$ mkdir packages
Download procps 3.3.9-9 that is used on Debian Jessie.
# wget --directory-prefix packages http://ftp.us.debian.org/debian/pool/main/p/procps/procps_3.3.9-9_amd64.deb --2018-03-31 15:21:10-- http://ftp.us.debian.org/debian/pool/main/p/procps/procps_3.3.9-9_amd64.deb Resolving ftp.us.debian.org (ftp.us.debian.org)... 208.80.154.15, 128.30.2.26, 128.61.240.89, ... Connecting to ftp.us.debian.org (ftp.us.debian.org)|208.80.154.15|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 235612 (230K) [application/octet-stream] Saving to: _packages/procps_3.3.9-9_amd64.deb_ procps_3.3.9-9_amd64.deb 100%[=====================================================================================================================================>] 230.09K 671KB/s in 0.3s 2018-03-31 15:21:10 (671 KB/s) - _packages/procps_3.3.9-9_amd64.deb_ saved [235612/235612]
Create a bin directory.
jessie-free$ mkdir bin
Display package contents.
jessie-free$ ar t packages/procps_3.3.9-9_amd64.deb debian-binary control.tar.gz data.tar.xz
Extract data.tar.xz archive that contains program files.
jessie-free$ ar -vx packages/procps_3.3.9-9_amd64.deb data.tar.xz x - data.tar.xz
Search for free binary.
jessie-free$ xz --decompress --stdout data.tar.xz | tar --list --wildcards --file - .*free ./usr/bin/free
Extract free binary.
jessie-free$ xz --decompress --stdout data.tar.xz | tar --extract --strip-components 3 --verbose --directory bin --file - ./usr/bin/free ./usr/bin/free
Delete data.tar.xz archive.
jessie-free$ rm data.tar.xz
Inspect extracted file.
jessie-free$ file bin/free bin/free: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=1c8c568fca62e6d1472643dd9aad39632fe24cb2, stripped
Inspect missing libraries.
jessie-free$ ldd bin/free
linux-vdso.so.1 (0x00007ffd3bb9e000)
libprocps.so.3 => not found
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f1bb9fca000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f1bb9c2b000)
/lib64/ld-linux-x86-64.so.2 (0x000055a7a9468000)
libprocps.so file is provided by the corresponding libprocps package.
$ dpkg-query -S libprocps.so libprocps6:amd64: /lib/x86_64-linux-gnu/libprocps.so.6 libprocps6:amd64: /lib/x86_64-linux-gnu/libprocps.so.6.0.0
Create a libs directory.
jessie-free$ mkdir libs
Download libprocps3 package.
$ wget --directory-prefix packages http://ftp.us.debian.org/debian/pool/main/p/procps/libprocps3_3.3.9-9_amd64.deb --2018-03-31 15:40:11-- http://ftp.us.debian.org/debian/pool/main/p/procps/libprocps3_3.3.9-9_amd64.deb Resolving ftp.us.debian.org (ftp.us.debian.org)... 128.61.240.89, 208.80.154.15, 128.30.2.26, ... Connecting to ftp.us.debian.org (ftp.us.debian.org)|128.61.240.89|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 56320 (55K) [application/octet-stream] Saving to: _packages/libprocps3_3.3.9-9_amd64.deb_ libprocps3_3.3.9-9_amd64.deb 100%[=====================================================================================================================================>] 55.00K 270KB/s in 0.2s 2018-03-31 15:40:12 (270 KB/s) - _packages/libprocps3_3.3.9-9_amd64.deb_ saved [56320/56320]
Display package contents.
jessie-free$ ar t packages/libprocps3_3.3.9-9_amd64.deb debian-binary control.tar.gz data.tar.xz
Extract data.tar.xz archive that contains program files.
jessie-free$ ar vx packages/libprocps3_3.3.9-9_amd64.deb data.tar.xz x - data.tar.xz
Search for libprocps.so library files.
jessie-free$ xz --decompress --stdout data.tar.xz | tar --list --wildcards --file - .*/libprocps\.so.* ./lib/x86_64-linux-gnu/libprocps.so.3.0.0 ./lib/x86_64-linux-gnu/libprocps.so.3
Extract free binary.
jessie-free$ xz --decompress --stdout data.tar.xz | tar --extract --strip-components 3 --verbose --directory libs --wildcards --file - ./lib/x86_64-linux-gnu/libprocps.so.* ./lib/x86_64-linux-gnu/libprocps.so.3.0.0 ./lib/x86_64-linux-gnu/libprocps.so.3
Delete data.tar.xz archive.
jessie-free$ rm data.tar.xz
Use LD_LIBRARY_PATH to temporarily indicate the location of the additional directory (or colon-separated directories), which will be searched first for available libraries before the standard set of directories to ensure that there are no missing ones.
jessie-free$ LD_LIBRARY_PATH=./libs/ ldd bin/free
linux-vdso.so.1 (0x00007fff24abb000)
libprocps.so.3 => ./libs/libprocps.so.3 (0x00007efeb374c000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007efeb3545000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007efeb31a6000)
/lib64/ld-linux-x86-64.so.2 (0x00005629ffe59000)
Execute a free command using LD_LIBRARY_PATH environment variable.
jessie-free$ LD_LIBRARY_PATH=./libs/ bin/free -m
total used free shared buffers cached
Mem: 15975 61 15913 658 0 56
-/+ buffers/cache: 4 15970
Swap: 15623 910 14713
Inspect the directory tree created during the previous steps.
jessie-free$ tree -A
.
├── bin
│ └── free
├── libs
│ ├── libprocps.so.3 -> libprocps.so.3.0.0
│ └── libprocps.so.3.0.0
└── packages
├── libprocps3_3.3.9-9_amd64.deb
└── procps_3.3.9-9_amd64.deb
3 directories, 5 files