smartree · November 21, 2019 06:17 · Oct 12, 2015 · Oct 12, 2015 · Oct 12, 2015 · Oct 12, 2015
diff --git a/install-gcc48-linuxbrew-centos6.md b/install-gcc48-linuxbrew-centos6.md
@@ -2,6 +2,8 @@
 
 The GCC distributed with CentOS 6 is 4.4.7, which is pretty outdated. I'd like to use gcc 4.8+. Also, when trying to install [Linuxbrew](https://github.com/Homebrew/linuxbrew) you run into a dependency loop where Homebrew's gcc depends on zlib, which depends on gcc. Here's how I solved the problem.
 
+_Note_: Requires `sudo` privileges. 
+
 ### Resources:
 
 - <http://superuser.com/a/676337/88393>: Forum response on using CERN's open Scientific Linux distribution of RHEL's developer toolset.

diff --git a/install-gcc48-linuxbrew-centos6.md b/install-gcc48-linuxbrew-centos6.md
@@ -59,6 +59,12 @@ GNU Fortran (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
 ...
 ```
 
+_Optional_: Permanently enable scl toolchain by putting this in your `.bashrc` (warning: don't try to use the `scl enable devtoolset-2 bash` command from before in your .bashrc. This spawns a new bash shell, and if that's in your .bashrc, it creates a new shell, which loads your .bashrc, which creates a new shell, etc.)
+
+```
+source /opt/rh/devtoolset-2/enable
+```
+
 ### Installing Linuxbrew
 
 Enable the SCL environment:

diff --git a/install-gcc48-linuxbrew-centos6.md b/install-gcc48-linuxbrew-centos6.md
@@ -20,25 +20,25 @@ CentOS release 6.7 (Final)
 
 Import CERN's GPG key:
 
-```bash
+```
 sudo rpm --import http://ftp.scientificlinux.org/linux/scientific/5x/x86_64/RPM-GPG-KEYs/RPM-GPG-KEY-cern
 ```
 
 Save repository information as `/etc/yum.repos.d/slc6-devtoolset.repo` on your system:
 
-```bash
+```
 wget -O /etc/yum.repos.d/slc6-devtoolset.repo http://linuxsoft.cern.ch/cern/devtoolset/slc6-devtoolset.repo
 ```
 
 Install:
 
-```bash
+```
 sudo yum install devtoolset-2
 ```
 
 Enable the environment: 
 
-```bash
+```
 scl enable devtoolset-2 bash
 
 ```
@@ -63,36 +63,36 @@ GNU Fortran (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
 
 Enable the SCL environment:
 
-```bash
+```
 scl enable devtoolset-2 bash
 
 ```
 
 Create symlinks to your new gcc/g++/gfortran:
 
-```bash
+```
 ln -s $(which gcc) `brew --prefix`/bin/gcc-$(gcc -dumpversion |cut -d. -f1,2)
 ln -s $(which g++) `brew --prefix`/bin/g++-$(g++ -dumpversion |cut -d. -f1,2)
 ln -s $(which gfortran) `brew --prefix`/bin/gfortran-$(gfortran -dumpversion |cut -d. -f1,2)
 ```
 
 Install Linuxbrew:
 
-```bash
+```
 ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/linuxbrew/go/install)"
 ```
 
 Add these to your `.bashrc`, and source it:
 
-```bash
+```
 export PATH="$HOME/.linuxbrew/bin:$PATH"
 export MANPATH="$HOME/.linuxbrew/share/man:$MANPATH"
 export INFOPATH="$HOME/.linuxbrew/share/info:$INFOPATH"
 ```
 
 Test your installation:
 
-```bash
+```
 brew install hello
 brew test hello
 brew remove hello

diff --git a/install-gcc48-linuxbrew-centos6.md b/install-gcc48-linuxbrew-centos6.md
@@ -0,0 +1,99 @@
+## Installing gcc 4.8 and Linuxbrew on CentOS 6
+
+The GCC distributed with CentOS 6 is 4.4.7, which is pretty outdated. I'd like to use gcc 4.8+. Also, when trying to install [Linuxbrew](https://github.com/Homebrew/linuxbrew) you run into a dependency loop where Homebrew's gcc depends on zlib, which depends on gcc. Here's how I solved the problem.
+
+### Resources:
+
+- <http://superuser.com/a/676337/88393>: Forum response on using CERN's open Scientific Linux distribution of RHEL's developer toolset.
+- <http://linux.web.cern.ch/linux/devtoolset/>: CERN's developer toolset installation instructions.
+- <https://github.com/Homebrew/linuxbrew/wiki/Standalone-Installation>: Instructions for a standalone installation of Homebrew. 
+- <https://twitter.com/sjackman>: Shaun Jackman -- the hero who maintains Linuxbrew.
+
+### Upgrading gcc
+
+First, verify which version of CentOS you're using:
+
+```
+$ cat /etc/centos-release
+CentOS release 6.7 (Final)
+```
+
+Import CERN's GPG key:
+
+```bash
+sudo rpm --import http://ftp.scientificlinux.org/linux/scientific/5x/x86_64/RPM-GPG-KEYs/RPM-GPG-KEY-cern
+```
+
+Save repository information as `/etc/yum.repos.d/slc6-devtoolset.repo` on your system:
+
+```bash
+wget -O /etc/yum.repos.d/slc6-devtoolset.repo http://linuxsoft.cern.ch/cern/devtoolset/slc6-devtoolset.repo
+```
+
+Install:
+
+```bash
+sudo yum install devtoolset-2
+```
+
+Enable the environment: 
+
+```bash
+scl enable devtoolset-2 bash
+
+```
+
+Test the environment: 
+
+```
+$ gcc --version
+gcc (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
+...
+
+$ g++ --version
+g++ (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
+...
+
+$ gfortran --version
+GNU Fortran (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15)
+...
+```
+
+### Installing Linuxbrew
+
+Enable the SCL environment:
+
+```bash
+scl enable devtoolset-2 bash
+
+```
+
+Create symlinks to your new gcc/g++/gfortran:
+
+```bash
+ln -s $(which gcc) `brew --prefix`/bin/gcc-$(gcc -dumpversion |cut -d. -f1,2)
+ln -s $(which g++) `brew --prefix`/bin/g++-$(g++ -dumpversion |cut -d. -f1,2)
+ln -s $(which gfortran) `brew --prefix`/bin/gfortran-$(gfortran -dumpversion |cut -d. -f1,2)
+```
+
+Install Linuxbrew:
+
+```bash
+ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/linuxbrew/go/install)"
+```
+
+Add these to your `.bashrc`, and source it:
+
+```bash
+export PATH="$HOME/.linuxbrew/bin:$PATH"
+export MANPATH="$HOME/.linuxbrew/share/man:$MANPATH"
+export INFOPATH="$HOME/.linuxbrew/share/info:$INFOPATH"
+```
+
+Test your installation:
+
+```bash
+brew install hello
+brew test hello
+brew remove hello
+```