pwd: /out/package
ppid: 52104
   1: WRITELN echo 123 > 1.txt
   2: WRITELN echo 321 > 2.txt
   3: WRITELN cat < 1.txt | cat >> 2.txt
   4: WRITELN cat 1.txt
   5: WRITELN cat 2.txt
   6: WRITELN ls
   7: WRITELN exit
exit: 0

mumsh $ mumsh $ mumsh $ mumsh $ 123
mumsh $ 321
123
mumsh $ 1.txt
2.txt
driver
mumsh
mumsh_memory_check
mumsh $ exit

mumsh $ mumsh $ mumsh $ mumsh $ 123
mumsh $ 321
123
mumsh $ 1.txt
2.txt
driver
mumsh
mumsh_memory_check
mumsh $ exit