bash - trim off the last 4 characters

[Garrett85]

I'M wanting to write my own command/script for compiling my c++ files. I use g++ -g -Wall filename.cpp -o filename

I'M trying to figure out how I can trip of the last four characters (.cpp) from a string. Any ideas?

[Nutster]

Take a look at the make command, which is made specifically for this kind of thing. Just create a Makefile in the same directory as the source file(s). You can even try this without a Makefile and make MyPrg will compile the file based on the defaults.

#Makefile
MyPrg:
        g++ -O3 -Wall MyPrg.cpp -o MyPrg
        strip MyPrg

debug:  MyPrg.cpp
        g++ -g -Wall MyPrg.cpp -o MyPrg
        touch debug

clean:
        -rm debug MyPrg

To use this Makefile to generate MyPrg, run the make command.
~/src/cpp/MyPrg> make
This will use the first rule to make MyPrg from the given source file. If MyPrg.cpp changes, then calling make will recompile MyPrg.
~/src/cpp/MyPrg> make debug
This will use the debug: rule to create MyPrg to make that version of the program.
~/src/cpp/MyPrg> make clean
This will remove the files generated using this Makefile.

[Garrett85]

I was trying to avoid hard coding MyPrg.cpp and MyPrg. I was going to use ${1} for command line arguments. So I would simply type "compile MyPrg.cpp" and my script would run g++ -g -Wall ${1} -o ${1 - last 4 characters}

[Watael]

hi,

v="myFile.cpp"
((${#v}>4)) && echo "${v:: -4}"

or

v="myFile.cpp"
echo "${v%.cpp}"

[rojomoke]

Also, check out the basename command