The Linux version of Autodesk Nastran has a number of small changes associated with some aspects of the execution when compared with the Windows version. These variations are documented here.
Initialization File Redundancy
In the event that an initialization file is not found on the command line, the Linux version of Nastran will examine, in order, each of the following locations for an initialization file. This will trigger a series of Linux specific warnings to inform you that this is occurring and the initialization file it detects and uses. Used correctly, this mechanism allows you to set default parameters on a per-user basis, or simply the default system initialization file. It will use the first initialization file it finds in the following sequence:
- <command line>
An initialization file found on the command line takes precedence.
- ./Nastran.INI
Nastran will look in the current working directory for this initialization file.
- ~/.Nastran.INI
Nastran will look for a “hidden” initialization file placed in the users home directory. The extra ‘.’ before the filename means it will not be visible to an ‘ls’ command unless you use the ‘-a’ option to the ‘ls’ command. Place this file here if you always use the same options for your simulations.
- /opt/Autodesk/Nastran_2026/ini/Nastran.INI
This is the default initialization file configured at the time of installation. It will most likely not be editable by a standard user.
Supported Filename and Directory Naming Conventions
Support for spaces or other punctuation marks in the filenames and folder names has been enabled. However, it should be noted that it requires additional levels of precaution to escape, or quote, the filenames and folder names on the terminal command line when executing Autodesk Nastran. This has the potential to lead to an error and it is considered safer to avoid this possibility by avoiding the use of spaces and other punctuation marks in the names of files and folder names (underscores and dashes can be used without additional effort.
Additionally, we recommend using absolute pathnames, which start with a leading '/', instead of the abbreviations '.', '..', or '~'. These options are enabled, although you are advised to test this before using extensively.
Temporary Directories
The Autodesk Nastran Linux version is intended to be used on cluster systems where there may be multiple users running Autodesk Nastran or a user running multiple simulations simultaneously. To ensure that each running instance of Nastran on a Linux system does not interfere with another running instance, the Linux version of Autodesk Nastran will create a unique directory within the location specified by the FILESPEC(x) directives. The name of this unique directory will have the format “nastmp_XXXXXX”, where the XXXXXX will be replaced at the time of execution by a sequence of system generated characters to ensure uniqueness.
Upon successful completion, this folder will be removed. Should an Autodesk Nastran simulation be interrupted, this folder will not be automatically removed. In that case, it may be necessary to manually remove this folder.