Some commands doesn't work on shared servers

[kicaj]

When I run deploy my server return something like this:

[Deployer\Exception\RuntimeException (126)]
The command "readlink /home/account_id/public_html/release" failed.

Exit Code: 126 (Invoked command cannot execute)

Host Name: example.org

================
bash: line 1: /usr/bin/readlink: Permission denied

It's something like safe-mode on my shared server.
But "readlink" is accessible from php scripts.

So... there is some alternative option to run commands like this using PHP?

[kicaj]

Commands like reallink and realpath doesn't work,
but command like below, work great:
ls -l {{deploy_path}}/release | awk '{print$NF}'
ls -l {{deploy_path}}/release | sed "s/.*->//"

What do you think?