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How to get readlink -e on M1 Macs which also works when used in bash scripts?

I am using several bash scripts for build and deployment processes which use readlink with the -e option. Since this option is not available I followed this suggest to install coreutils and create a symbolink between greadlink and readlink. This worked perfectly on my Intel mac but when I recently switch to M1 mac I realized that the path to greadlink and readlink are changed so I tried this:

ln -s /opt/homebrew/bin/greadlink /usr/bin/readlink

Which gave me an error: Operation not permitted

I realised that this is because of the System Integrity Protection

How can I still use readlink -e in my bash scripts without deactivate the System Integrity Protection?

Solution

  • One approach is to create a script named readlink somewhere in your PATH with the following content.

    #!/bin/sh

exec greadlink "$@"
    • Just make sure that the relative path of script named readlink comes before /usr/bin/ since the system readlink is in /usr/bin when you run:
    declare -p PATH

    or

    echo "$PATH"

    An example how to do it:

    Create a directory in ~/, name it scripts since it will have script as contents.

    mkdir -p ~/scripts

    Edit ~/.bashrc to include the created directory in the PATH env variable.

    if [[ :$PATH: != *:$HOME/scripts:* ]]; then
  PATH=$HOME/scripts:$PATH
fi

    Source ~/.bashrc

    source ~/.bashrc

    Create a script name readlink inside the ~/scripts directory with the following contents:

    #!/bin/sh

exec /opt/homebrew/bin/greadlink "$@"

    Make it executable

    chmod +x ~/scripts/readlink

    Check which readlink is the first in PATH

    type -a readlink

    Output should be something like.

    readlink is /home/zlZimon/scripts/readlink
readlink is /usr/bin/readlink
    • Note that the current work around is for a single user, or rather the user that has scripts directory in PATH, for a system wide approach one can use the path from homebrew or /usr/local/ or whichever default is available for all users.