Below are commands to verify the exact version of a package installed in Linux. Root prompt or sudo is not required!
Red Hat or CentOS:
$ rpm -qa | grep package
$ rpm -qa | grep openssl openssl-1.0.0-20.el6_2.5.x86_64
If a package is not installed, the output will return nothing:
$ rpm -qa | grep firefox $
Ubuntu or Debian:
$ dpkg -s package
$ dpkg -s openssl Package: openssl Status: install ok installed Priority: optional Section: utils Installed-Size: 844 Maintainer: Ubuntu Developers
Architecture: i386 Version: 0.9.8k-7ubuntu8.13 Depends: libc6 (>= 2.7), libssl0.9.8 (>= 0.9.8k-1), zlib1g (>= 1:1.1.4) Suggests: ca-certificates, openssl-doc Conflicts: ssleay (<< 0.9.2b) Conffiles: /etc/ssl/openssl.cnf 0b1cf9a835b829131d630b7c2fe55f3c Description: Secure Socket Layer (SSL) binary and related cryptographic tools This package contains the openssl binary and related tools. . It is part of the OpenSSL implementation of SSL. . You need it to perform certain cryptographic actions like: - Creation of RSA, DH and DSA key parameters; - Creation of X.509 certificates, CSRs and CRLs; - Calculation of message digests; - Encryption and decryption with ciphers; - SSL/TLS client and server tests; - Handling of S/MIME signed or encrypted mail. Original-Maintainer: Debian OpenSSL Team
If a package is not installed, the output will look similar to:
$ dpkg -s firefox Package `firefox' is not installed and no info is available. Use dpkg --info (= dpkg-deb --info) to examine archive files, and dpkg --contents (= dpkg-deb --contents) to list their contents.