[sbt] How to check sbt version?

How do I check which version of sbt I'm running?

I have the bash file set up that uses sbt-launch.jar, and it works, but

$ sbt version

only shows the "project version" (0.1) and

$ sbt --version

does nothing.

Doing sbt sbt-version led to some error as

[error] Not a valid command: sbt-version (similar: writeSbtVersion, session)
[error] Not a valid project ID: sbt-version
[error] Expected ':'
[error] Not a valid key: sbt-version (similar: sbtVersion, version, sbtBinaryVersion)
[error] sbt-version
[error]            ^

As you can see the hint similar: sbtVersion, version, sbtBinaryVersion, all of them work but the correct one is generated by sbt sbtVersion

From within the sbt shell

sbt:venkat> about
[info] This is sbt 1.3.3
...

run sbt console then type sbtVersion to check sbt version, and scalaVersion for scala version

Running the command, "sbt sbt-version" will simply output your current directory and the version number.

$ sbt sbt-version
[info] Set current project to spark (in build file:/home/morgan/code/spark/)
[info] 0.13.8

sbt about then enter to get SBT version

In SBT 0.13 and above, you can use the sbtVersion task (as pointed out by @steffen) or about command (as pointed out by @mark-harrah)

There's a difference how the sbtVersion task works in and outside a SBT project. When in a SBT project, sbtVersion displays the version of SBT used by the project and its subprojects.

$ sbt sbtVersion
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Updating {file:/Users/jacek/.sbt/0.13/plugins/}global-plugins...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] Loading project definition from /Users/jacek/oss/scalania/project
[info] Set current project to scalania (in build file:/Users/jacek/oss/scalania/)
[info] exercises/*:sbtVersion
[info]  0.13.1-RC5
[info] scalania/*:sbtVersion
[info]  0.13.1-RC5

It's set in project/build.properties:

jacek:~/oss/scalania
$ cat project/build.properties
sbt.version=0.13.1-RC5

The same task executed outside a SBT project shows the current version of the executable itself.

jacek:~
$ sbt sbtVersion
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Updating {file:/Users/jacek/.sbt/0.13/plugins/}global-plugins...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] Set current project to jacek (in build file:/Users/jacek/)
[info] 0.13.0

When you're outside, the about command seems to be a better fit as it shows the sbt version as well as Scala's and available plugins.

jacek:~
$ sbt about
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to jacek (in build file:/Users/jacek/)
[info] This is sbt 0.13.0
[info] The current project is {file:/Users/jacek/}jacek 0.1-SNAPSHOT
[info] The current project is built against Scala 2.10.2
[info] Available Plugins: com.typesafe.sbt.SbtGit, com.typesafe.sbt.SbtProguard, growl.GrowlingTests, org.sbtidea.SbtIdeaPlugin, com.timushev.sbt.updates.UpdatesPlugin
[info] sbt, sbt plugins, and build definitions are using Scala 2.10.2

You may want to run 'help about' to read its documentation:

jacek:~
$ sbt 'help about'
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to jacek (in build file:/Users/jacek/)
Displays basic information about sbt and the build.

For the sbtVersion setting, the inspect command can help.

$ sbt 'inspect sbtVersion'
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to jacek (in build file:/Users/jacek/)
[info] Setting: java.lang.String = 0.13.0
[info] Description:
[info]  Provides the version of sbt.  This setting should be not be modified.
[info] Provided by:
[info]  */*:sbtVersion
[info] Defined at:
[info]  (sbt.Defaults) Defaults.scala:67
[info] Delegates:
[info]  *:sbtVersion
[info]  {.}/*:sbtVersion
[info]  */*:sbtVersion
[info] Related:
[info]  */*:sbtVersion

The version setting that people seem to expect to inspect to know the SBT version is to set The version/revision of the current module.

$ sbt 'inspect version'
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to jacek (in build file:/Users/jacek/)
[info] Setting: java.lang.String = 0.1-SNAPSHOT
[info] Description:
[info]  The version/revision of the current module.
[info] Provided by:
[info]  */*:version
[info] Defined at:
[info]  (sbt.Defaults) Defaults.scala:102
[info] Reverse dependencies:
[info]  *:projectId
[info]  *:isSnapshot
[info] Delegates:
[info]  *:version
[info]  {.}/*:version
[info]  */*:version
[info] Related:
[info]  */*:version

When used in a SBT project the tasks/settings may show different outputs.

You can use sbt about

Example: 
    C:\Users\smala>sbt about
    [info] Set current project to smala (in build file:/C:/Users/smala/)
    [info] This is sbt 0.13.6
    [info] The current project is {file:/C:/Users/smala/}smala 0.1-SNAPSHOT
    [info] The current project is built against Scala 2.10.4
    [info] Available Plugins: sbt.plugins.IvyPlugin, sbt.plugins.JvmPlugin,   sbt.plugins.CorePlugin, sbt.plugins.JUnitXmlReportPlugin
    [info] sbt, sbt plugins, and build definitions are using Scala 2.10.4"