OK, I thought I would try one last update and see if it gets me anywhere. I've created a very small test case. This should not build anything, it just tests the path settings. Also I've setup the path so there are no spaces. The is the smallest, simplest test case I could come up with. This makefile will set the path, echo the path, run avr-gcc -v with the full path specified and then try to run it without the full path specified. It should find avr-gcc in the path on the second try, but does not. makefile TOOLCHAIN := /Users/justinzaun/Desktop/AVRBuilder.app/Contents/Resources/avrchain PATH := ${TOOLCHAIN}/bin:${PATH} export PATH all: @echo ${PATH} @echo -------- "${TOOLCHAIN}/bin/avr-gcc" -v @echo -------- avr-gcc -v output JUSTINs-MacBook-Air:Untitled justinzaun$ make /Users/justinzaun/Desktop/AVRBuilder.app/Contents/Resources/avrchain/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin -------- "/Users/justinzaun/Desktop/AVRBuilder.app/Contents/Resources/avrchain/bin/avr-gcc" -v Using built-in specs. COLLECT_GCC=/Users/justinzaun/Desktop/AVRBuilder.app/Contents/Resources/avrchain/bin/avr-gcc COLLECT_LTO_WRAPPER=/Users/justinzaun/Desktop/AVRBuilder.app/Contents/Resources/avrchain/bin/../libexec/gcc/avr/4.6.3/lto-wrapper Target: avr Configured with: /Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../gcc/configure --prefix=/Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../build/ --exec-prefix=/Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../build/ --datadir=/Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../build/ --target=avr --enable-languages=c,objc,c++ --disable-libssp --disable-lto --disable-nls --disable-libgomp --disable-gdbtk --disable-threads --enable-poison-system-directories Thread model: single gcc version 4.6.3 (GCC) -------- avr-gcc -v make: avr-gcc: No such file or directory make: *** [all] Error 1 JUSTINs-MacBook-Air:Untitled justinzaun$ Original Question I'm trying to set the path from within the makefile. I can't seem to do this on OSX. Setting the path with PATH := /new/bin/:$(PATH) does not work. See my makefile below. makefile PROJECTNAME = Untitled # Name of target controller # (e.g. 'at90s8515', see the available avr-gcc mmcu # options for possible values) MCU = atmega640 # id to use with programmer # default: PROGRAMMER_MCU=$(MCU) # In case the programer used, e.g avrdude, doesn't # accept the same MCU name as avr-gcc (for example # for ATmega8s, avr-gcc expects 'atmega8' and # avrdude requires 'm8') PROGRAMMER_MCU = $(MCU) # Source files # List C/C++/Assembly source files: # (list all files to compile, e.g. 'a.c b.cpp as.S'): # Use .cc, .cpp or .C suffix for C++ files, use .S # (NOT .s !!!) for assembly source code files. PRJSRC = main.c \ utils.c # additional includes (e.g. -I/path/to/mydir) INC = # libraries to link in (e.g. -lmylib) LIBS = # Optimization level, # use s (size opt), 1, 2, 3 or 0 (off) OPTLEVEL = s ### You should not have to touch anything below this line ### PATH := /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/bin:/usr/bin:/bin:$(PATH) CPATH := /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/include # HEXFORMAT -- format for .hex file output HEXFORMAT = ihex # compiler CFLAGS = -I. $(INC) -g -mmcu=$(MCU) -O$(OPTLEVEL) \ -fpack-struct -fshort-enums \ -funsigned-bitfields -funsigned-char \ -Wall -Wstrict-prototypes \ -Wa,-ahlms=$(firstword \ $(filter %.lst, $(<:.c=.lst))) # c++ specific flags CPPFLAGS = -fno-exceptions \ -Wa,-ahlms=$(firstword \ $(filter %.lst, $(<:.cpp=.lst)) \ $(filter %.lst, $(<:.cc=.lst)) \ $(filter %.lst, $(<:.C=.lst))) # assembler ASMFLAGS = -I. $(INC) -mmcu=$(MCU) \ -x assembler-with-cpp \ -Wa,-gstabs,-ahlms=$(firstword \ $(<:.S=.lst) $(<.s=.lst)) # linker LDFLAGS = -Wl,-Map,$(TRG).map -mmcu=$(MCU) \ -lm $(LIBS) ##### executables #### CC=avr-gcc OBJCOPY=avr-objcopy OBJDUMP=avr-objdump SIZE=avr-size AVRDUDE=avrdude REMOVE=rm -f ##### automatic target names #### TRG=$(PROJECTNAME).out DUMPTRG=$(PROJECTNAME).s HEXROMTRG=$(PROJECTNAME).hex HEXTRG=$(HEXROMTRG) $(PROJECTNAME).ee.hex # Start by splitting source files by type # C++ CPPFILES=$(filter %.cpp, $(PRJSRC)) CCFILES=$(filter %.cc, $(PRJSRC)) BIGCFILES=$(filter %.C, $(PRJSRC)) # C CFILES=$(filter %.c, $(PRJSRC)) # Assembly ASMFILES=$(filter %.S, $(PRJSRC)) # List all object files we need to create OBJDEPS=$(CFILES:.c=.o) \ $(CPPFILES:.cpp=.o) \ $(BIGCFILES:.C=.o) \ $(CCFILES:.cc=.o) \ $(ASMFILES:.S=.o) # Define all lst files. LST=$(filter %.lst, $(OBJDEPS:.o=.lst)) # All the possible generated assembly # files (.s files) GENASMFILES=$(filter %.s, $(OBJDEPS:.o=.s)) .SUFFIXES : .c .cc .cpp .C .o .out .s .S \ .hex .ee.hex .h .hh .hpp # Make targets: # all, disasm, stats, hex, writeflash/install, clean all: $(TRG) $(TRG): $(OBJDEPS) $(CC) $(LDFLAGS) -o $(TRG) $(OBJDEPS) #### Generating assembly #### # asm from C %.s: %.c $(CC) -S $(CFLAGS) $< -o $@ # asm from (hand coded) asm %.s: %.S $(CC) -S $(ASMFLAGS) $< > $@ # asm from C++ .cpp.s .cc.s .C.s : $(CC) -S $(CFLAGS) $(CPPFLAGS) $< -o $@ #### Generating object files #### # object from C .c.o: $(CC) $(CFLAGS) -c $< -o $@ # object from C++ (.cc, .cpp, .C files) .cc.o .cpp.o .C.o : $(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@ # object from asm .S.o : $(CC) $(ASMFLAGS) -c $< -o $@ #### Generating hex files #### # hex files from elf .out.hex: $(OBJCOPY) -j .text \ -j .data \ -O $(HEXFORMAT) $< $@ .out.ee.hex: $(OBJCOPY) -j .eeprom \ --change-section-lma .eeprom=0 \ -O $(HEXFORMAT) $< $@ #### Information #### info: @echo PATH: @echo "$(PATH)" $(CC) -v which $(CC) #### Cleanup #### clean: $(REMOVE) $(TRG) $(TRG).map $(DUMPTRG) $(REMOVE) $(OBJDEPS) $(REMOVE) $(LST) $(REMOVE) $(GENASMFILES) $(REMOVE) $(HEXTRG) error JUSTINs-MacBook-Air:Untitled justinzaun$ make avr-gcc -I. -g -mmcu=atmega640 -Os -fpack-struct -fshort-enums -funsigned-bitfields -funsigned-char -Wall -Wstrict-prototypes -Wa,-ahlms=main.lst -c main.c -o main.o make: avr-gcc: No such file or directory make: *** [main.o] Error 1 JUSTINs-MacBook-Air:Untitled justinzaun$ If I change my CC= to include the full path: CC=/Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/bin/avr-gcc then it finds it, but this doesn't seem the correct way to do things. For instance its trying to use the system as not the one in the correct path. update - Just to be sure, I'm adding the output of my ls command too so everyone knows the file exist. Also I've added a make info target to the makefile and showing that output as well. JUSTINs-MacBook-Air:Untitled justinzaun$ ls /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/bin ar avr-elfedit avr-man avr-strip objcopy as avr-g++ avr-nm avrdude objdump avr-addr2line avr-gcc avr-objcopy c++ ranlib avr-ar avr-gcc-4.6.3 avr-objdump g++ strip avr-as avr-gcov avr-ranlib gcc avr-c++ avr-gprof avr-readelf ld avr-c++filt avr-ld avr-size ld.bfd avr-cpp avr-ld.bfd avr-strings nm JUSTINs-MacBook-Air:Untitled justinzaun$ Output of make info with the \ in my path JUSTINs-MacBook-Air:Untitled justinzaun$ make info PATH: /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin avr-gcc -v make: avr-gcc: No such file or directory make: *** [info] Error 1 JUSTINs-MacBook-Air:Untitled justinzaun$ Output of make info with the \ not in my path JUSTINs-MacBook-Air:Untitled justinzaun$ make info PATH: /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR Builder.app/Contents/Resources/avrchain/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin avr-gcc -v make: avr-gcc: No such file or directory make: *** [info] Error 1 JUSTINs-MacBook-Air:Untitled justinzaun$ update - When I have my CC set to include the full path as described above, this is the result of make info. JUSTINs-MacBook-Air:Untitled justinzaun$ make info PATH: /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR Builder.app/Contents/Resources/avrchain/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/bin/avr-gcc -v Using built-in specs. COLLECT_GCC=/Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR Builder.app/Contents/Resources/avrchain/bin/avr-gcc COLLECT_LTO_WRAPPER=/Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR Builder.app/Contents/Resources/avrchain/bin/../libexec/gcc/avr/4.6.3/lto-wrapper Target: avr Configured with: /Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../gcc/configure --prefix=/Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../build/ --exec-prefix=/Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../build/ --datadir=/Users/justinzaun/Development/AVRBuilder/Packages/gccobj/../build/ --target=avr --enable-languages=c,objc,c++ --disable-libssp --disable-lto --disable-nls --disable-libgomp --disable-gdbtk --disable-threads --enable-poison-system-directories Thread model: single gcc version 4.6.3 (GCC) which /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR\ Builder.app/Contents/Resources/avrchain/bin/avr-gcc /Users/justinzaun/Library/Developer/Xcode/DerivedData/AVR_Builder-gxiykwiwjywvoagykxvmotvncbyd/Build/Products/Debug/AVR Builder.app/Contents/Resources/avrchain/bin/avr-gcc JUSTINs-MacBook-Air:Untitled justinzaun$