210

In Linux, how do I check if a library is installed or not? (from the command line of course).

In my specific case now, I want to check whether libjpeg is installed.

1
  • What distribution are you using ?
    – radius
    Aug 16, 2009 at 16:09

10 Answers 10

275

To do this in a distro-independent* fashion you can use ldconfig with grep, like this:

ldconfig -p | grep libjpeg

If libjpeg is not installed, there will be no output. If it is installed, you will get a line for each version available.

Replace libjpeg by any library you want, and you have a generic, distro-independent* way of checking for library availability.

If for some reason the path to ldconfig is not set, you can try to invoke it using its full path, usually /sbin/ldconfig.

**99% of the times*

13
  • 2
    This should be accepted as the answer. Great!
    – user105523
    Dec 19, 2013 at 13:53
  • 1
    It's not possible to use this for checking for the dev version (headers) of a library, right?
    – andig
    Aug 14, 2015 at 8:08
  • 2
    Can you specify 99% times? bash: ldconfig: command not found on Debian x64 Jessie with xfce! This is the recomended debian release on the debian website... Oct 12, 2015 at 13:46
  • 4
    @TomášZato: ldconfig is not available (command not found shows up) if you try to run it without being superuser.
    – Gauthier
    Aug 29, 2016 at 9:01
  • 2
    /sbin/ldconfig -p works for me without needing to be root. Nov 9, 2016 at 4:12
35

You can check with the package manager of your distribution (aptitude, yum, ...) but as you did not give your distribution I can't give you the right command.

Another way can be to run gcc -ljpeg, if you get 'ld: library not found for -ljpeg' it means that gcc has not found the library (but it don't mean that it's not installed), if you get something like 'Undefined symbols: "_main", referenced from: ...' it means that libjpeg has been found.

locate libjpeg; ls /usr/lib/libjpeg*; ls /lib/libjpeg* are some other way to find if the lib in installed in the system

There is many other way to check that, if you give us more context (why you need to check if libjpeg is installed) we could give you the best solution for your specific case.

0
18

I use the whereis utility.

Sample:

l1feh4ck3r@xxx:~$ whereis libjpeg
libjpeg: /usr/lib/libjpeg.so /usr/lib/libjpeg.a /usr/lib/libjpeg.la
1
  • does not work for me Apr 19, 2021 at 5:33
13

I use this:

gcc -lpng

When the lib is installed, it yields:

undefined reference to 'main'

When the lib is not installed:

cannot find -lpng
12

For deb-based distribution you can do

dpkg -s packagename

Or if you know the filename only, use

locate filename

The filename is usually libsomething.so[.version].

4
  • 1
    The filename can also be something like "libsomething.a" for static version.
    – radius
    Aug 16, 2009 at 16:40
  • I find dpkg -s limited in utility, because it wants the actual package name, which may differ subtly or significantly from the library itself. I use dpkg -s|grep LIBRARY Aug 16, 2009 at 16:41
  • 2
    @dinomite apt-file is your friend :)
    – radius
    Aug 16, 2009 at 16:50
  • @DrewStephens doing that gives dpkg-query: error: --status needs at least one package name argument Apr 19, 2021 at 5:37
4

On Redhat based systems, one can use pkg-config to verify if a library is installed or not. Many rpm binaries actually make the same checks before proceeding with installation, so we can reasonably rely on its veracity.

pkg-config --cflags jpeg

pkg-config --libs jpeg

pkg-config --cflags "jpeg >= 1.0.0" # for version check
pkg-config  --modversion jpeg | awk -F. '{ printf "0x%02X%02X%02X\n",$1,$2,$3 }' #version check
0
2

This is done by configuration tools on linux all the time.

Look at this Tutorial about autoconf and KDevelop.

Other tricks would use commands like ldconfig and dpkg.

2

On Ubuntu 20.04, I am able to display a wealth of relevant information for a package using aptitude.

% aptitude show libssl-dev
Package: libssl-dev                      
Version: 1.1.1f-1ubuntu2.1
State: installed
Automatically installed: no
Multi-Arch: same
Priority: optional
Section: libdevel
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Architecture: amd64
Uncompressed Size: 8,006 k
Depends: libssl1.1 (= 1.1.1f-1ubuntu2.1)
Suggests: libssl-doc
Conflicts: libssl1.0-dev
Breaks: libssl-dev:i386 (!= 1.1.1f-1ubuntu2.1)
Replaces: libssl-dev:i386 (< 1.1.1f-1ubuntu2.1)
Description: Secure Sockets Layer toolkit - development files
 This package is part of the OpenSSL project's implementation of the SSL and TLS cryptographic protocols for secure communication over
 the Internet. 
 
 It contains development libraries, header files, and manpages for libssl and libcrypto.
Homepage: https://www.openssl.org/

To find which package would provide a particular file I have found apt-file very useful - some instructions are here: https://linuxhint.com/find_which_package_contains_specific_file_ubuntu/

% apt-file search 'libjpeg.so'          
darktable: /usr/lib/x86_64-linux-gnu/darktable/plugins/imageio/format/libjpeg.so
libjpeg-turbo8: /usr/lib/x86_64-linux-gnu/libjpeg.so.8
libjpeg-turbo8: /usr/lib/x86_64-linux-gnu/libjpeg.so.8.2.2
libjpeg-turbo8-dev: /usr/lib/x86_64-linux-gnu/libjpeg.so
libjpeg62: /usr/lib/x86_64-linux-gnu/libjpeg.so.62
libjpeg62: /usr/lib/x86_64-linux-gnu/libjpeg.so.62.0.0
libjpeg62-dev: /usr/lib/x86_64-linux-gnu/libjpeg.so
libjpeg9: /usr/lib/x86_64-linux-gnu/libjpeg.so.9
libjpeg9: /usr/lib/x86_64-linux-gnu/libjpeg.so.9.4.0
libjpeg9-dev: /usr/lib/x86_64-linux-gnu/libjpeg.so
libxine2-misc-plugins: /usr/lib/x86_64-linux-gnu/xine/plugins/2.7/xineplug_decode_libjpeg.so
nsight-systems: /usr/lib/nsight-systems/Host-x86_64/libjpeg.so.8

1

You can also try using dpkg to check whether it is installed.

dpkg --list | grep [some_key_words_of_your_lib]

Besides, on CentOS, you can try this.

rpm -qa [lib_name]

2
  • Note: Will work only for Debian based distros
    – ALex_hha
    Oct 25, 2018 at 21:33
  • @ALex_hha Yes, thank you, this should be emphasized. On CentOS or red hat based systems, use pkg-config instead.
    – Scott Yang
    Oct 31, 2018 at 9:23
0

as per Kim above

dpkg -s packagename

[[ $(dpkg -s libsox-fmt-pulse 2> /dev/null) =~ "is not installed" ]] && sudo apt install libsox-fmt-pulse # for hdmi output

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