How to understand or How to check whether o software is 32 or 64 bit

[charitosha]

Hello everybody,

I recently was able to install the Geekbench software by using the help provided in this forum (older posts)
I was not able to install it on my own however because the 32 bit library was missing.

My question is this, by seeing the below how can i understand or suspect that i am missing a library


[IMG]/home/hariton/Pictures/Screenshot_2021-10-13_17-31-30.png[/IMG]


Thanks in advance!

Edit: for a reason the picture do not work. however what i see in the folder is:
geekbench5 (green color, thus executable)
geekbench.plar (white color)
geekbench_x86_64 (green color, thus executable)

[TheFu]

Use the "file" command.

I found a very old backup of a 16.04 desktop that was 32-bit:

# file esniper 
esniper: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=cebbc46154d476652a57ae05666eff10ceb7c342, with debug_info, not stripped

When I try to run it on a 20.04 system (64-bit only), I see

$ esniper 
esniper: error while loading shared libraries: libcurl.so.4: cannot open shared object file: No such file or directory

However, that library as a 64-bit version, exists on the machine:

$ ll /usr/lib/x86_64-linux-gnu/libcurl.so*
lrwxrwxrwx 1 root root     16 Sep 10 10:28 /usr/lib/x86_64-linux-gnu/libcurl.so.4 -> libcurl.so.4.6.0
-rw-r--r-- 1 root root 588424 Sep 10 10:28 /usr/lib/x86_64-linux-gnu/libcurl.so.4.6.0

The 'file' for that library:

$ file /usr/lib/x86_64-linux-gnu/libcurl.so.4.6.0 
/usr/lib/x86_64-linux-gnu/libcurl.so.4.6.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=c74e00b5bbd2ef8308c8c53e4e8a0385604ee2b4, stripped

My 16.04 32-bit backup doesn't have system stuff, so I can't find libcurl.so.4 under /usr/lib/ . I don't backup that area on my systems. I do backup /usr/local/*, but not things that would be installed with a normal installation and patch cycle. Sorry.

Not certain I've answered your question, but use 'file' to check any compiled library or program for the architecture it uses.

Just for fun, I looked on a Raspberry Pi - that's an ARM CPU.

$ file /usr/lib/arm-linux-gnueabihf/libcurl.so.4.5.0
/usr/lib/arm-linux-gnueabihf/libcurl.so.4.5.0: ELF 32-bit LSB shared object, ARM, EABI5 version 1 (SYSV), dynamically linked, BuildID[sha1]=d8406507a355832fb2cc13712575f2dc603dcb7d, stripped

32-bit ... because that CPU is 32-bit.

Compiled library and program developers have to worry about these things all the time. Basically it is for C/C++/C#/pascal/rust people. Java and all the scripted language devs don't have to worry about this.

[HermanAB]

Similarly, you can use ldd to list all the shared libraries called by a program.

[charitosha]

Thanks both of you for the reply!

What i like from the ldd command is that it list all the required shared libraries (which is very nice), however the manpages state that it is somewhat dangerous because it might execute the program as well. And due to this, they suggest to use objdump command.
Now im not quite sure how "real" the threat is with the ldd, but with objdump you can find out pretty much anything you might need. it is a bit complected thought

Lastly, the file command is very helpful as well.

I am not going to close this thread yet, because i would like to ask something about the file and objdump commands

[TheFu]

I've always used nm and ar for looking inside libraries. I don't remember them showing 32/64-bitness. Those two tools don't work on programs, just libraries.

[Dennis N]

As you have seen, ldd will identify libraries such as:

libstdc++.so.6 => /usr/lib/i386-linux-gnu/libstdc++.so.6 (0xb7688000)

but that's only half the job - you also need to identify what package provides that library.

Without using any special utilitity, that's here:
https://packages.ubuntu.com

Also, ldd may not show all the required 32-bit libraries. I have installed 32-bit games where it doesn't.