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The J install folder is j701 (j64-701 for 64 bit systems). A standard install puts the J folder in your HOME folder.

Admin privilege is not required for a standard install or for web updates.

User and temp files are in HOME folder j701-user (or j64-701-user).

Doing the install in a protected folder path such as "Program Files..." or /usr/... requires admin privilege and will require admin privilege for web updates. Installing in other than HOME can be a nuisance and has no compelling benefit with the possible exception of an install for Multiple Users.

JE (J Engine) is a shared library that executes J sentences and is the system core. JE is j.dll in Windows, in Linux, and libj.dylib in Mac.

JFE (J Front End) is a user interface to JE.

Jconsole is a console JFE. It is jconsole.exe in Windows and jconsole in Linux and Mac.

Unix hardlinks to JFE are not supported and symlinks must have an absolute path.

Folder Summary


  jinstall: j701          or j64-701
  juser:    j701-user     or j64-user-701


  Vista,Win7: \Users\name
  XP:         \Documents and Settings\name
  Linux:      /home/name
  Mac:        /Users/name


  J32 on Win 32: C:\Program Files
  J64 on Win 64: C:\Program Files
  J32 on Win 64: C:\Program Files (x86)
  Unix:          /usr/...

standard install:


system install:


custom install:


custom install with profilex.ijs:


Windows and Windows64

The installer creates J folder j701 and Program Group j701 (j64-701 for Windows64).

Yellow J icon interrupts a running J program.

Gray J icon runs Jconsole (Ctrl+D exits).

Windows XP: HOME is "\Documents and Settings\username".

Linux and Linux64

If you downloaded to ~/temp , do a standard J32 install with: ...> sh ~/temp/ -install For J64 use 64 instead of 32. Run without -install for options.

This unpacks the J folder in your home folder. A linux32 file creates j701 and linux64 creates j64-701.

In the following examples, if your install is linux64, use j64-701 instead of j701.

Run Jconsole:

...> ~/j701/bin/jconsole

For easy Jconsole start, create a symbolic link in a folder in PATH. For example,

...$ ln -s ~/j701/bin/jconsole jc
...$ sudo mv jc /usr/bin/jc

Mac (intel and powerpc)

Standard install is to use Finder to copy j701 folder from the mounted disk image to your home folder.

Copy does a complete replace of an existing J folder and you need extra steps if there are files you want to protect or carry forward.

Yellow J icon interrupts a running J program.

Run Jconsole in a Terminal window (Finder Applications Utilities Terminal):

...$ ~/j701/bin/jconsole

For easy Jconsole start, create a symbolic link in a folder in PATH. For example,

...$ ln -s ~/j701/bin/jconsole jc
...$ sudo mv jc /usr/bin/jc

An option is to copy j701 folder to Applications. This requires admin privilege for the install and for subsequent web updates. An Applications install can be used by other users.

A 3rd option, for casual use, is to just run J from the mounted disk image.

Multiple Users

Multiple users can share a single J install. Different users automatically get their own user and temp folders in their HOME folder.You can share a standard install with the J folder in the HOME directory of the user who is primarily responsible for J and updates and maintenance.

Alternatively you can do the install (or move an existing install) to a folder you feel is more appropriate. If you move a Windows install you have to manually edit the jsoftware-j701 icon properties to reference the new location.

You will want to provide users a convenient way to run J and this varies across platforms.


To allow all users to see the jsoftware-j701 Program Group, copy it from your HOME Programs folder to the public Programs folder: 1. right click Start button and click Open 2. right click jsoftware-j701 and click copy 3. right click Start button and click Open All Users 4. right click Programs folder and click paste


Create desktop launch icons and symlinks as appropriate.


If you put j701 in Applications, the J icons are already there in the j701 folder. If J is somewhere else you can create alias links for the J icons in Applications as follows: 1. in J folder press ctrl, click red J icon, click Make Alias 2. drag j701 alias to Applications 3. rename alias to just be j701 4. repeat steps for yellow J icon if desired Create a symlink to jconsole as appropriate.

Customized User Folder

The normal folder for user and temp files is HOME j701-user (or j64-701-user). Override this by creating profilex.ijs in your J bin folder.

bin\profilex_template.ijs is a template of what you want in profilex.ijs for the override. Study profilex_template.ijs before making your profilex.ijs file. Backup and be careful as errors may prevent J from starting properly.

USB Memory Stick

You can copy a J folder to a USB memory stick for a complete and portable J system. If you want the J user folders to be on the memory stick you need to create a proflilex.ijs file in the memory stick J bin folder. See Customized User Folder for more information. You will want to edit profilex.ijs to have user in the install folder.

If you don't put profilex.ijs in the J folder on the memory stick, the J system will use HOME for the user folder.