The scl enable ... command creates a new shell; you've probably ended up with several nested layers of shells if you've been testing this. If you exit, you'll probably see the gcc --version output from the base system. See how deeply-nested you are with something like pstree -s $$.
To run gcc --version with scl, just put the command on the scl line:
scl enable devtoolset-9 'gcc --version'
Reference: The Red Hat Developer Toolset 9 User Guide (pdf).
Answer from Jeff Schaller on Stack ExchangeThe scl enable ... command creates a new shell; you've probably ended up with several nested layers of shells if you've been testing this. If you exit, you'll probably see the gcc --version output from the base system. See how deeply-nested you are with something like pstree -s $$.
To run gcc --version with scl, just put the command on the scl line:
scl enable devtoolset-9 'gcc --version'
Reference: The Red Hat Developer Toolset 9 User Guide (pdf).
to get the script to act as you want it to, you need the scl command to modify the current bash session rather than spawn a new one.
you can do it this way
#!/usr/bin/env bash
# switch to GCC9 environment for the duration of the script
source scl_source enable devtoolset-9
gcc --version
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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
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 [ 
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 [ $_recursion == "false" ]; then
_i=0
_recursion="true"
while [ 
{#_scls[@]} ]; do
_scl_scriptlet_path="${_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]} $X_SCLS"
fi;
_i=
_i+1))
done
_scls=()
_scl_prefixes=()
_scl_scriptlet_name=""
_recursion="false"
fi
A work-around that I found is to set gnome-terminal to run
bash -c "$HOME/.bashrc; exec zsh"
as a custom command in place of the default shell, which is equivalent to opening a terminal emulator with
gnome-terminal -- bash -c "$HOME/.bashrc; exec zsh"
adapted from here.
It seems you could also use:
source /opt/rh/devtoolset-8/enable
Tested on RHEL7.6 for package rh-php73, it worked:
source /opt/rh/rh-php73/enable
Found the hint here
I am using CentOS 7.9 and I encountered the same problem after following instructions here to install and run gcc 11. I tried launching different versions of gcc and found only devtoolset-9 works, which corresponds to the file devtoolset-9 in /etc/scl/conf/ folder. So I copied devtoolset-9 to devtoolset-11 in the same folder, and gcc 11 gets working.
I ran into the same issue that you are facing and this is how I got it fixed:
- Just want to be careful, you need to exist the Terminal and open a fresh one to start. This way, you are not under any devtoolset's bash.
- Go to /opt/rh folder, run command ls -la to see if you have any devtoolset-* folder there. Let's say you have devtoolset-8, proceed step 2.
- Go to /etc/scl/prefixes folder, if you don't see devtoolset-8 file, you can create a new one as devtoolset-8, and type 1 line: /opt/rh, then save and quit that file.
- Once you are done, you can call: scl enable devtoolset-8 -- bash w/o any error. Good luck
I had this problem as well. I don't know why scl was failing to enable the environment, but I was able to get it to load with source /opt/rh/devtoolset-7/enable.
It is because of your settings in .bashrc and/or .bash_profile. scl appends its path to gcc7 before starting your new bash shell, but the path to gcc is default to the old gcc4 again because your .bashrc appends /usr/bin to the path when starting the new bash, and it supersedes the scl settings. The solution is to use the "enable" script directly. That way no further path settings annoy you.
using scl enable actually opens a new shell inside your current one, which is quite unclean, especially if done from a login script.
You should place, instead, in your ~/.bash_profile:
source /opt/rh/rh-nginx18/enable
or:
source scl_source enable rh-nginx18
The latter is more "elegant" as it is independent from the actual installation path.
This has the effect of loading the environment in your current shell.
Redhat proposes placing a file in /etc/profile.d, i.e. for python:
$ cat /etc/profile.d/enablepython33.sh
#!/bin/bash
source scl_source enable python33
As this works for the devtools under centos for me you could try this.