Gmx pdb2gmx error

GROMACS version:2024.1
GROMACS modification: Yes
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I’ve installed gromacs 2024.1 in ubuntu. When using gmx pdb2gmx -f pro.pdb -o pro.gro …command following error comes out

Error in user input:
Invalid command-line options
In command-line option -f
Failed to access file ‘alanine.pdb’.
The file could not be opened.
Reason: Permission denied
(call to fopen() returned error code 13)

You don’t have the pdb file in the directory,

No, the pdb file is present in the working directory.

check this, also your command is -f pro.pdb,