[artymk4]

I have Ubuntu and I installed OpenFOAM from source. It is installed in /home/<user>/OpenFOAM/OpenFOAM-v1806


When I run "icoFoam -help" in Terminal, I get this:

Command 'icoFoam' not found, but can be installed with:

sudo apt install openfoam

I manually edited file /home/<user>/.bashrc and added this at the end:
source ~/OpenFOAM/OpenFOAM-v1806/etc/bashrc


After some reading I found out I might need to compile Openfoam first. So I ran ./Allwmake and got this error. What am I doing wrong?

$ ./Allwmake 
========================================
2018-11-23 15:43:15 +0100
Starting OpenFOAM-v1806 
  Gcc system compiler
  linux64GccDPInt32Opt, with SYSTEMOPENMPI openmpi-system

flex -o /home/ubuntwo/OpenFOAM/OpenFOAM-v1806/wmake/platforms/linux64Gcc/wmkdep.c wmkdep.l && gcc -m64 -DOPENFOAM=1806 -Dlinux64 -DWM_ARCH_OPTION=64 -DWM_DP -DWM_LABEL_SIZE=32 -Wall -O3   -fPIC /home/ubuntwo/OpenFOAM/OpenFOAM-v1806/wmake/platforms/linux64Gcc/wmkdep.c -o /home/ubuntwo/OpenFOAM/OpenFOAM-v1806/wmake/platforms/linux64Gcc/wmkdep
/bin/sh: 1: flex: not found
Makefile:76: recipe for target '/home/ubuntwo/OpenFOAM/OpenFOAM-v1806/wmake/platforms/linux64Gcc/wmkdep' failed
make: *** [/home/ubuntwo/OpenFOAM/OpenFOAM-v1806/wmake/platforms/linux64Gcc/wmkdep] Error 127

[wyldckat]

Quick answer: "flex not found" means that the "flex" package hasn't been installed. You should follow the instructions given here: https://www.openfoam.com/documentati...quirements.php - it's indicated at the start of the instructions for source code page that you provided