我的系統中已經安裝的gcc如下：
[root@gksrv Desktop]# gcc --version
gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18)
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
我在系統上安裝了 gcc-4.8.2，輸入後得到的輸出的最後部分make install如下：
Libraries have been installed in:
/root/gcc-4.8.2/lib/../lib64
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,-rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
----------------------------------------------------------------------
test -z "/root/gcc-4.8.2/share/info" || /bin/mkdir -p "/root/gcc-4.8.2/share/info"
/usr/bin/install -c -m 644 /root/Downloads/objdir/../gcc-4.8.2/libgomp/libgomp.info '/root/gcc-4.8.2/share/info'
install-info --info-dir='/root/gcc-4.8.2/share/info' '/root/gcc-4.8.2/share/info/libgomp.info'
test -z "/root/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/finclude" || /bin/mkdir -p "/root/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/finclude"
/usr/bin/install -c -m 644 omp_lib.h omp_lib.f90 omp_lib.mod omp_lib_kinds.mod '/root/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/finclude'
test -z "/root/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/include" || /bin/mkdir -p "/root/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/include"
/usr/bin/install -c -m 644 omp.h '/root/gcc-4.8.2/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/include'
make[4]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libgomp'
make[3]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libgomp'
make[2]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libgomp'
make[2]: Entering directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm'
Making install in testsuite
make[3]: Entering directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm/testsuite'
make[4]: Entering directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm/testsuite'
make[4]: Nothing to be done for `install-exec-am'.
make[4]: Nothing to be done for `install-data-am'.
make[4]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm/testsuite'
make[3]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm/testsuite'
make[3]: Entering directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm'
true DO=all multi-do # make
make[4]: Entering directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm'
true DO=install multi-do # make
test -z "/root/gcc-4.8.2/lib/../lib64" || /bin/mkdir -p "/root/gcc-4.8.2/lib/../lib64"
/usr/bin/install -c -m 644 libitm.spec '/root/gcc-4.8.2/lib/../lib64'
test -z "/root/gcc-4.8.2/lib/../lib64" || /bin/mkdir -p "/root/gcc-4.8.2/lib/../lib64"
/bin/sh ./libtool --mode=install /usr/bin/install -c libitm.la '/root/gcc-4.8.2/lib/../lib64'
libtool: install: /usr/bin/install -c .libs/libitm.so.1.0.0 /root/gcc-4.8.2/lib/../lib64/libitm.so.1.0.0
libtool: install: (cd /root/gcc-4.8.2/lib/../lib64 && { ln -s -f libitm.so.1.0.0 libitm.so.1 || { rm -f libitm.so.1 && ln -s libitm.so.1.0.0 libitm.so.1; }; })
libtool: install: (cd /root/gcc-4.8.2/lib/../lib64 && { ln -s -f libitm.so.1.0.0 libitm.so || { rm -f libitm.so && ln -s libitm.so.1.0.0 libitm.so; }; })
libtool: install: /usr/bin/install -c .libs/libitm.lai /root/gcc-4.8.2/lib/../lib64/libitm.la
libtool: install: /usr/bin/install -c .libs/libitm.a /root/gcc-4.8.2/lib/../lib64/libitm.a
libtool: install: chmod 644 /root/gcc-4.8.2/lib/../lib64/libitm.a
libtool: install: ranlib /root/gcc-4.8.2/lib/../lib64/libitm.a
libtool: finish: PATH="/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.121-1.b13.el6.x86_64/bin:/usr/lib64/qt-3.3/bin:/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.121-1.b13.el6.x86_64/bin:/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/apache/apache-ant-1.9.9/bin:/root/bin:/usr/apache/apache-ant-1.9.9/bin:/sbin" ldconfig -n /root/gcc-4.8.2/lib/../lib64
ldconfig: /root/gcc-4.8.2/lib/../lib64/libstdc++.so.6.0.18-gdb.py is not an ELF file - it has the wrong magic bytes at the start.
----------------------------------------------------------------------
Libraries have been installed in:
/root/gcc-4.8.2/lib/../lib64
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,-rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
----------------------------------------------------------------------
test -z "/root/gcc-4.8.2/share/info" || /bin/mkdir -p "/root/gcc-4.8.2/share/info"
/usr/bin/install -c -m 644 /root/Downloads/objdir/../gcc-4.8.2/libitm/libitm.info '/root/gcc-4.8.2/share/info'
install-info --info-dir='/root/gcc-4.8.2/share/info' '/root/gcc-4.8.2/share/info/libitm.info'
make[4]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm'
make[3]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm'
make[2]: Leaving directory `/root/Downloads/objdir/x86_64-unknown-linux-gnu/libitm'
make[1]: Leaving directory `/root/Downloads/objdir'
在輸入 gcc -v 之後，我得到以下輸出：
[root@gksrv objdir]# gcc -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-ppl --with-cloog --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.4.7 20120313 (Red Hat 4.4.7-18) (GCC)
為什麼它沒有檢測到gcc-4.8.2？如何讓系統gcc-4.8.2每次輸入後都顯示gcc -v？
答案1
更改您的 PATH 環境變量，以便它gcc-4.8.2位於您的路徑中並且之前可以找到gcc-4.4.7