How to permanently enable newer version of software installed from SCL repo?

Question

On CentOS 6.4:

I installed a newer version of devtoolset (1.1) and was wondering how I would go about permanently setting these to be default. Right now, when I ssh into my server running CentOS 6, I have to run this command scl enable devtoolset-1.1 bash

I tried adding it to ~/.bashrc and simply pasting it on the very last line, without success.

Answer 1

In your ~/.bashrc or ~/.bash_profile Simply source the "enable" script provided with the devtoolset. For example, with the Devtoolset 2, the command is:

source /opt/rh/devtoolset-2/enable

or

source scl_source enable devtoolset-2

Lot more efficient: no forkbomb, no tricky shell

Answer 2

An alternative of source /opt/rh/devtoolset-4/enable is

source scl_source enable devtoolset-4

The above shell script scl_source is more elegant than using a hard coded path (may be different on another machine). However scl_source does less because /opt/rh/devtoolset-4/enable uses scl_source and other stuff.

To use scl_source you may have to upgrade package scl-utils

yum update scl-utils  # old scl-utils versions miss scl_source

Quick copy-paste

echo 'source scl_source enable devtoolset-4' >> ~/.bashrc
    # Do not forget to change the version ↑

---

Source code for curious people

An example of scl_source source code:
https://gist.github.com/bkabrda/6435016

The scl_source installed on my Red Hat 7.1

#!/bin/bash

_scl_source_help="Usage: source scl_source <action> [<collection> ...]

Don't use this script outside of SCL scriptlets!

Options:
    -h, --help    display this help and exit"

if [ $# -eq 0 -o $1 = "-h" -o $1 = "--help" ]; then
    echo "$_scl_source_help"
    return 0
fi


if [ -z "$_recursion" ]; then
    _recursion="false"
fi
if [ -z "$_scl_scriptlet_name" ]; then
    # The only allowed action in the case of recursion is the same
    # as was the original
    _scl_scriptlet_name=$1
fi
shift 1

if [ -z "$_scl_dir" ]; then
    # No need to re-define the directory twice
    _scl_dir=/etc/scl/conf
    if [ ! -e $_scl_dir ]; then
        _scl_dir=/etc/scl/prefixes
    fi
fi

for arg in "$@"; do
    _scl_prefix_file=$_scl_dir/$arg
    _scl_prefix=`cat $_scl_prefix_file 2> /dev/null`
    if [ $? -ne 0 ]; then
        echo "Can't read $_scl_prefix_file, $arg is probably not installed."
        return 1
    fi

    # First check if the collection is already in the list
    # of collections to be enabled
    for scl in ${_scls[@]}; do
        if [ $arg == $scl ]; then
            continue 2
        fi
    done

    # Now check if the collection isn't already enabled
    /usr/bin/scl_enabled $arg > /dev/null 2> /dev/null
    if [ $? -ne 0 ]; then
        _scls+=($arg)
        _scl_prefixes+=($_scl_prefix)
    fi;
done

if [ $_recursion == "false" ]; then
    _i=0
    _recursion="true"
    while [ $_i -lt ${#_scls[@]} ]; do
        _scl_scriptlet_path="${_scl_prefixes[$_i]}/${_scls[$_i]}/${_scl_scriptlet_name}"
        source "$_scl_scriptlet_path"
        if [ $? -ne 0 ]; then
            echo "Can't source $_scl_scriptlet_name, skipping."
        else
            export X_SCLS="${_scls[$_i]} $X_SCLS"
        fi;
        _i=$(($_i+1))
    done
    _scls=()
    _scl_prefixes=()
    _scl_scriptlet_name=""
    _recursion="false"
fi

Answer 3

The problem is that scl enable devtoolset-1.1 bash creates a new bash shell. So when you put it in your .bashrc, it creates a new shell...which loads your .bashrc, which runs scl enable devtoolset-1.1 bash, which creates a new shell, which loads your .bashrc... Forkbomb!

You probably want something like this in your .bashrc:

if [ "$(gcc -dumpversion)" != "4.7.2" ]; then 
  scl enable devtoolset-1.1 bash
fi

or

if [ -z "$TRIEDSCLDEVTOOLSET" ]; then
  export TRIEDSCLDEVTOOLSET=true
  scl enable devtoolset-1.1 bash
fi

• the first will continue to forkbomb if devtoolset-1.1 does not contain gcc 4.7.2, and will also fail to work if your native environment has gcc 4.7.2.
• this creates a new shell, as above. So when you create your terminal window or ssh session, you will be in two bash sessions, and have to exit twice.

Answer 4

An alternate way to locate the script mentioned in other answers is to let your package manager tell you where it lives.

This is what we run to pull in the dotnet tools on our RHEL/CentOS vagrant machines.

source $(rpm -ql rh-dotnet20-runtime|grep -E /enable$)

Answer 5

For enabling it across systems for all users. Please make changes in "/etc/profile" as below:

source scl_source enable devtoolset-2