Obtaining Random LIne from A file

*To*: mathgroup at smc.vnet.net*Subject*: [mg129816] Obtaining Random LIne from A file*From*: Ramiro Barrantes <rbarrant at uvm.edu>*Date*: Sat, 16 Feb 2013 01:08:44 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Hello, I would like to get a random line from a file, I know this can be done with Mathematica but I am playing with using sed to see if it goes faster, say I want to get line 1000 In mathematica it would be: <<"! sed -n p1000 filename.txt" However, I am trying to put the filename as a variable, say filename="hugefile.txt" cmd="! sed -n p1000 "<>filename <<cmd does not work. How can I do this? Lastly, I am getting a randomline using mathematica doing: getRandomLine[file_, n_] := Block[{i = RandomInteger[{1, n}], str = OpenRead[file], res}, Skip[str, "String", i]; res = Read[str, Expression]; Close[str]; res[[2]] ] However, it is very slow so I was going to try with sed.Any suggestions? Thanks in advance, Ramiro