How do I check if file exists in Makefile so I can delete it

Question

In the clean section of my Makefile I am trying to check if the file exists before deleting permanently  I use this code but I receive errors   What s wrong with it    if   -a myApp    then      rm myApp  fi   I get this error message   if   -a myApp     bin sh  Syntax error  end of file unexpected  expecting  then    make       clean  Error 2

User · Answer

The problem is when you split your command over multiple lines. So, you can either use the \ at the end of lines for continuation as above or you can get everything on one line with the && operator in bash.

Then you can use a test command to test if the file does exist, e.g.:

test -f myApp && echo File does exist

-f file True if file exists and is a regular file.

-s file True if file exists and has a size greater than zero.

or does not:

test -f myApp || echo File does not exist
test ! -f myApp && echo File does not exist

The test is equivalent to [ command.

[ -f myApp ] && rm myApp   # remove myApp if it exists

and it would work as in your original example.

See: help [ or help test for further syntax.

User · Answer

It s strange to see so many people using shell scripting for this  I was looking for a way to use native makefile syntax  because I m writing this outside of any target  You can use the wildcard function to check if file exists    ifeq    UNAME  Darwin       SHELL     opt local bin bash      OS X     true  else ifneq     wildcard  etc redhat-release        OS RHEL    true  else      OS DEB     true      SHELL     bin bash  endif    Update   I found a way which is really working for me   ifneq     wildcard   PATH TO FILE            FILE EXISTS   1 else     FILE EXISTS   0 endif

User · Answer

The second top answer mentions ifeq  however  it fails to mention that these must be on the same level as the name of the target  e g   to download a file only if it doesn t currently exist  the following code could be used  download  ifeq     wildcard   glob c       curl     -o glob c endif    THIS DOES NOT WORK  download      ifeq     wildcard   glob c           curl     -o glob c     endif

User · Answer

FILE1    usr bin perl FILE2    nofile  ifeq    shell test -e   FILE1   amp  amp  echo -n yes  yes      RESULT1   FILE1  exists  else     RESULT1   FILE1  does not exist  endif  ifeq    shell test -e   FILE2   amp  amp  echo -n yes  yes      RESULT2   FILE2  exists  else     RESULT2   FILE2  does not exist  endif  all       echo   RESULT1       echo   RESULT2    execution results   bash gt  make  usr bin perl exists   nofile does not exist

User · Answer

test   -f README md    echo  Support OpenSource    gt  gt  README md    If README md does not exist  do nothing  and exit successfully   Otherwise  append text to the end    If you use  amp  amp  instead of    then you generate an error when the file doesn t exist   Makefile 42  recipe for target  dostuff  failed make       dostuff  Error 1

User · Answer

Or just put it on one line  as make likes it   if   -a myApp    then rm myApp  fi

User · Answer

Missing a semicolon  if   -a myApp    then   rm myApp fi   However  I assume you are checking for existence before deletion to prevent an error message  If so  you can just use rm -f myApp which  forces  delete  i e  doesn t error out if the file didn t exist

User · Answer

It may need a backslash on the end of the line for continuation  although perhaps that depends on the version of make    if   -a myApp       then        rm myApp     fi

User · Answer

I was trying     -f   PROGRAM     amp  amp  cp -f   PROGRAM    INSTALLDIR    And the positive case worked but my ubuntu bash shell calls this TRUE and breaks on the copy     -f     amp  amp  cp -f   home user proto    bin  cp  missing destination file operand after   home user proto    bin     After getting this error  I google how to check if a file exists in make  and this is the answer

User · Answer

One line solution       -f   myfile    amp  amp  echo exists  One line solution with error action       -f   myfile    amp  amp  echo exists    echo not exists  Example used in my make clean directives  clean         -f   myfile    amp  amp  rm myfile    true  And make clean works without error messages

User · Answer

The answers like the one from  mark-wilkins using   to continue lines and   to terminate them in the shell or like the ones from  kenorb changing this to one line are good and will fix this problem     there s a simpler answer to the original problem  as  alexey-polonsky pointed out    Use the -f flag to rm so that it won t trigger an error   rm -f myApp   this is simpler  faster and more reliable   Just be careful not to end up with a slash and an empty variable  rm -f    myAppPath     NEVER DO THIS  you might end up deleting your system

User · Answer

ifneq     wildcard   PATH TO FILE            FILE EXISTS   1 else     FILE EXISTS   0 endif   This solution posted above works best  But make sure that you do not stringify the PATH TO FILE assignment E g    PATH TO FILE     usr local lib libhl   a    WILL NOT WORK   It must be   PATH TO FILE    usr local lib libhl   a

[makefile] How do I check if file exists in Makefile so I can delete it?

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