system commands from R containing single and double quotes

Question

[joe]

Hi all,

I have a system command which works fine from terminal;

samtools mpileup -r chr1:1-100 -B -Q 0 input.sort.bam | awk '{gsub("[^^]","",$5);print length($5)}' > ./output.txt

I would like to implement this from R, but can't figure out how to work around the requirement to have both single(') and double(") quotes within a string, as using an escaped quote (\') or (\") won't work as a system command;

sys.cmd <- paste0("samtools mpileup -r ",locus.of.interest," -B -Q 0 ",input.sort.bam,"|awk '",'{gsub("[^^]","",$5);print length($5)}',"'")
print(sys.cmd)
"samtools mpileup -r chr1:1-100 -B -Q 0 input.sort.bam | awk '{gsub(\"[^^]\",\"\",$5);print length($5)}'"
sys.output <- system(sys.cmd, intern=TRUE) # DOES NOT WORK BECAUE OF (\")

Any advice? Thanks!!!

[WouterDeCoster]

Have you looked at rsamtools? I am not sure if it has the functionality you are looking for, I just now it exists, and that such solutions are likely to be less tricky than the system call that you are trying here.

[joe]

Thanks! I'l try to implement the same with rsamtools/R ...but, I'm still really curious how to solve my initial problem