The LAMMPS Shell. An enhanced LAMMPS executable for interactive sessions. Overview ======== This is a program that functions very similar to the regular LAMMPS executable but has several modifications and additions that make it more powerful for interactive sessions, i.e. where you type LAMMPS commands from the prompt instead of reading them from a file. - It uses the readline and history libraries to provide command line editing and context aware TAB-expansion (details on that below). - When processing an input file with the '-in' or '-i' flag from the command line, it does not exit at the end of that input file but stops at a prompt, so that additional commands can be issued - Errors will not abort the shell but return to the prompt. - It has additional commands aimed at interactive use (details below). - Interrupting a calculation with CTRL-C will not terminate the session but rather enforce a timeout to cleanly stop an ongoing run (more info on timeouts is in the timer command documentation). These enhancements makes the LAMMPS shell an attractive choice for interactive LAMMPS sessions in graphical user interfaces. TAB-expansion ============= When writing commands interactively at the shell prompt, you can hit the TAB key at any time to try and complete the text. This completion is context aware and will expand any first word only to commands available in that executable. - For style commands it will expand to available styles of the corresponding category (e.g. pair styles after a pair_style command). - For "compute", "fix", or "dump" it will also expand only to already defined groups for the group-ID keyword. - For commands like "compute_modify", "fix_modify", or "dump_modify" it will expand to known compute/fix/dump IDs only. - When typing references to computes, fixes, or variables with a "c_", "f_", or "v_" prefix, respectively, then the expansion will to known compute/fix IDs and variable names. Variable name expansion is also available for the ${name} variable syntax. - In all other cases, expansion will be performed on filenames. Command line editing and history ================================ When typing commands, command line editing similar to what BASH provides is available. Thus it is possible to move around the currently line and perform various cut and insert and edit operations. Previous commands can be retrieved by scrolling up (and down) or searching (e.g. with CTRL-r). Also history expansion through using the exclamation mark '!' can be performed. Examples: '!!' will be replaced with the previous command, '!-2' will repeat the command before that, '!30' will be replaced with event number 30 in the command history list, and '!run' with the last command line that started with "run". Adding a ":p" to such a history expansion will result that the expansion is printed and added to the history list, but NOT executed. On exit the LAMMPS shell will write the history list to a file ".lammps_history" in the current working directory. If such a file exists when the LAMMPS shell is launched it will be read to populate the history list. This is realized via the readline library and can thus be customized with an ".inputrc" file in the home directory. For application specific customization, the LAMMPS shell uses the name "lammps-shell". For more information about using and customizing an application using readline, please see the available documentation at: http://www.gnu.org/s/readline/#Documentation Additional commands =================== The followind commands are added to the LAMMPS shell on top of the regular LAMMPS commands: - help (or ?) print a brief help message - history display the current command history list - clear_history wipe out the current command history list - pwd print current working directory - cd change current working directory (same as pwd if no directory) - mem print current and maximum memory usage - | execute as a shell command and return to the command prompt - exit exit the LAMMPS shell cleanly (unlike the "quit" command) Compilation =========== Compilation of the LAMMPS shell can be enabled by setting the CMake variable BUILD_LAMMPS_SHELL to "on" or using the makefile in the tools/lammps-shell folder to compile after building LAMMPS using the conventional make procedure. The makefile will likely need customization depending on the features and settings used for compiling LAMMPS. Limitations =========== The LAMMPS shell was not designed for use with MPI parallelization via "mpirun" or "mpiexec" or "srun".