Help
gmsh --info
Mesh and save without the GUI
gmsh carre.geo -2
The output file can be set by adding the option -o FileName. To mesh in 3D, replace -2 by -3.
Multi-Threading
If GMSH is compiled with OpenMP then mesh can be generated in parallel using NUM_THREADS threads:
gmsh file.geo -nt NUM_THREADS [...]
Modifying a value of a Constant: -setnumber
For example, to change the value of h to 10 :
gmsh L.geo -2 -setnumber h 10
To modify multiple values, the -setnumber option must be typed each time
gmsh L.geo -2 -setnumber h 10 -setnumber xmax 50
Log file
gmsh L.geo -2 $1>logfile