A unix-like pipe operator in R to perform CLI operations (or call R functions)

unix.R

sed = function(x, pattern) {
    mynames = names(x)
    x = sapply(x, function(i) {
           type = class(i)
           result = system(paste("echo ", i, " | sed ", pattern, sep=""), intern=TRUE)
           class(result) = type
           result
    })
    names(x) = mynames
    x
}

'%sed%' = function(x, pattern) {
    sed(x, pattern)
}

egrep = function(x, pattern) {
    stopifnot(class(pattern) == 'character' || class(pattern) == 'numeric')
    type = class(x)
    result = list()
    for (i in as.list(x)) {
        tryCatch({
            result = c(result,
                system(paste("echo ", i, " | grep ", pattern, sep=""), intern=TRUE))
        },
        error = function(e) {
            NULL
        },
        warning = function(w) {
            NULL
        })
    }
    class(result) = type
    result
}

'%grep%' = function(x, pattern) {
    egrep(x, pattern)
}

Here’s my unsolicited code review.