.cpp文件在编译后消失了

Question

I can't explain how absolutely frustrating this will be if there is no way for me to recover this file. Honestly, I feel like there isn't, but I need to understand what the hell happened so I can take preventative steps in the future. Essentially, I am making a simple OOP Project involving fake bank accounts in EMACS, and during compilation, the .cpp file with all of my class code up and vanishes.

Here are the terminal commands before and after the vanishing file:

    lin114-11:25% ls
    BankAccount.cpp  BankAccount.h  BankAccount.h~  main.cpp
    lin114-11:26% emacs &
    [1] 23359
    lin114-11:27% g++ -o BankAccount.cpp main.cpp
    /tmp/ccEXMM25.o: In function `main':
    main.cpp:(.text+0x67): undefined reference to `CheckingAccount::driver()'
    main.cpp:(.text+0x78): undefined reference to `CheckingAccount::~CheckingAccount()'
    main.cpp:(.text+0xa1): undefined reference to `CheckingAccount::~CheckingAccount()'
    main.cpp:(.text+0xcc): undefined reference to `CheckingAccount::~CheckingAccount()'
    /tmp/ccEXMM25.o: In function `CheckingAccount::CheckingAccount(double, int,                                                                                        
    std::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
    main.cpp:(.text._ZN15CheckingAccountC2EdiSs[_ZN15CheckingAccountC5EdiSs]+0x59):
    undefined reference to `vtable for CheckingAccount'
    collect2: ld returned 1 exit status
    lin114-11:28% ls
    BankAccount.h  BankAccount.h~  main.cpp

As you can see, BankAccount.cpp just up and disappears after compilation. What happened and is there anyway to recover the file?

Answer 1

When you do this:

g++ -o BankAccount.cpp main.cpp

you are telling g++ to compile main.cpp , and write the output to a file called BankAccount.cpp . So you over-write your source file with an executable.

Answer 2

juanchopanza explained what happened.

Depending on the way your Filesystem operates, there is still a ( slim, tiny ) chance however to retrieve part (or all) of it... :

df .  #to see which /dev/something partition is holding that current directory
dd if='/dev/something' of=- | cat -v | grep -n 'a_specific_string'  2>/dev/null | less

and be veeery patient
a_specific_string being a string that you know was in that file (and if possible probably nowhere else, to narrow down the search).

Then once you get some line numbers, you can dig around (note however that it's entirely possible that the file, if still somewhere, may be split among several different areas of the disk's partition, if your file was over an inode's length)

Then you could use the line numbers to retrieve the whole file

for example, if you only foudn it at line nnnn :

 dd if='/dev/something' of='-' | cat -v | awk ' ( (NR > (nnnn - 100) ) && (NR < (nnnn+100) ) { print ; }'  

(Printing 99 lines before up to 100 lines after the matching line)
(Adjust it more closely if you can, depending on the line you looked for and its place in the file)