There are 3 packages providing 'mailx' (as of Precise);
'heirloom-mailx' seems to be selected as the default one;
'mailutils' and 'heirloom-mailx' are located in 'universe', but 'bsd-mailx' is in 'main' (and therefore should be the default suggested one).
---
$ sudo apt-get install mailx
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package mailx is a virtual package provided by:
mailutils 1:2.2+dfsg1-5
heirloom-mailx 12.5-1build1
bsd-mailx 8.1.2-0.20111106cvs-1
You should explicitly select one to install.
E: Package 'mailx' has no installation candidate
---
$ sudo apt-get install exim4
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
exim4-base exim4-config exim4-daemon-light heirloom-mailx
Suggested packages:
eximon4 exim4-doc-html exim4-doc-info spf-tools-perl swaks
Recommended packages:
mailx
The following NEW packages will be installed:
exim4 exim4-base exim4-config exim4-daemon-light heirloom-mailx
0 upgraded, 5 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,923 kB of archives.
After this operation, 4,278 kB of additional disk space will be used.
Do you want to continue [Y/n]? n
Abort.
---
$ apt-cache madison mailutils heirloom-mailx bsd-mailx
mailutils | 1:2.2+dfsg1-5 | http://archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages
heirloom-mailx | 12.5-1build1 | http://archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages
bsd-mailx | 8.1.2-0.20111106cvs-1 | http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
---
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: bsd-mailx (not installed)
ProcVersionSignature: Ubuntu 3.2.0-24.39-generic 3.2.16
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
Date: Sat Jun 16 03:40:02 2012
SourcePackage: bsd-mailx
UpgradeStatus: No upgrade log present (probably fresh install)
bug in heirloom-mailx? see: mailx command sends mail body as attachment (noname)
http://