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perlzshgnu-parallel

Perl command inside GNU parallel?

I am trying to run this in parallel:

parallel perl -pe '!/^step/ && s/(\S+)/sprintf("%.2e", $1)/ge' {} > {}.fix ::: *

That is, I want to execute the perl command on all files in the current directory, in parallel. This is not working, but I have no idea why.

Comment: The perl command is fixing floating-point numbers in tables. See Replacing precision of floating point numbers in existing file.

Solution

  • In Bash you can make a function:

    doit() {
  perl -pe '!/^step/ && s/(\S+)/sprintf("%.2e", $1)/ge' "$1" > "$2"
}
export -f doit
parallel doit {} {}.fix ::: *

    Exporting functions in Zsh requires using a variable:

    doit() {
  perl -pe '!/^step/ && s/(\S+)/sprintf("%.2e", $1)/ge' "$1" > "$2"
}
PARALLEL_ENV="$(typeset -f doit)"
parallel doit {} {}.fix ::: *

    Alternatively you can quote the perl expression and the redirection (which will also work in Bash):

    parallel perl -pe \''!/^step/ && s/(\S+)/sprintf("%.2e", $1)/ge'\' {} '>' {}.fix ::: *