How to extract a subset of samples from plink .bed files

Question

[Raju]

Hello. I am trying to extract data from .bed file using the following command:

~/data/df$ plink --bed Obesity_Send.bed --bim Obesity_Send.bim --fam Obesity_Send.fam --keep-fam ii.txt --make-bed --out ii

Here is the plink log from problematic run.

PLINK v1.90b6.25 64-bit (5 Mar 2022) Options in effect: --bed Obesity_Send.bed --bim Obesity_Send.bim --fam Obesity_Send.fam --keep-fam ii.txt --make-bed --out ii

Hostname: cohort-700-l-0 Working directory: /home/jovyan/data/df Start time: Thu Mar 31 11:12:41 2022

Random number seed: 1648725161 30153 MB RAM detected; reserving 15076 MB for main workspace.

2655566 variants loaded from .bim file.

522 people (123 males, 399 females) loaded from .fam.

291 phenotype values loaded from .fam.

Error: Failed to open ii.txt.

End time: Thu Mar 31 11:12:42 2022

please help, since I'm new to plink

[4galaxy77]

Failed to open ii.txt probably means ii.txt isn't the current directory.

[Raju]

got it, i created ii.txt file and run the command then this error throwing:

log :

PLINK v1.90b6.25 64-bit (5 Mar 2022) Options in effect: --bed Obesity_Send.bed --bim Obesity_Send.bim --fam Obesity_Send.fam --keep-fam ii.txt --make-bed --out ii

Hostname: cohort-700-l-0 Working directory: /home/jovyan/data/df Start time: Thu Mar 31 11:53:41 2022

Random number seed: 1648727621 30153 MB RAM detected; reserving 15076 MB for main workspace.

2655566 variants loaded from .bim file.

522 people (123 males, 399 females) loaded from .fam.

291 phenotype values loaded from .fam.

Error: No people remaining after --keep-fam.

End time: Thu Mar 31 11:53:41 2022

[Raju]

Actually i need to extract sample id's, how to do so?