add varargs form of pipe

base/process.jl

@@ -157,6 +157,8 @@ end
 pipe(cmd::AbstractCmd, dest) = pipe(cmd, stdout=dest)
 pipe(src::Union(Redirectable,AbstractString), cmd::AbstractCmd) = pipe(cmd, stdin=src)
 
+pipe(a, b, c, d...) = pipe(pipe(a,b), c, d...)
+
 typealias RawOrBoxedHandle Union(UVHandle,UVStream,Redirectable,IOStream)
 typealias StdIOSet NTuple{3,RawOrBoxedHandle}
 

doc/stdlib/base.rst

@@ -659,11 +659,14 @@ System
    The ``dir`` keyword argument can be used to specify a working directory for the
    command.
 
-.. function:: pipe(from, to)
+.. function:: pipe(from, to, ...)
 
    Create a pipeline from a data source to a destination. The source and destination can
-   be commands, I/O streams, or strings, but at least one must be a command. Strings refer
-   to filenames.
+   be commands, I/O streams, strings, or results of other ``pipe`` calls. At least one
+   argument must be a command. Strings refer to filenames.
+   When called with more than two arguments, they are chained together from left to right.
+   For example ``pipe(a,b,c)`` is equivalent to ``pipe(pipe(a,b),c)``. This provides a more
+   concise way to specify multi-stage pipelines.
 
    **Examples**:
      * ``run(pipe(`ls`, `grep xyz`))``

test/spawn.jl

@@ -25,7 +25,7 @@ out = readall(`echo hello` & `echo world`)
 @test (run(`printf "       \033[34m[stdio passthrough ok]\033[0m\n"`); true)
 
 # Test for SIGPIPE being treated as normal termination (throws an error if broken)
-@unix_only @test (run(pipe(pipe(yes,`head`),DevNull)); true)
+@unix_only @test (run(pipe(yes,`head`,DevNull)); true)
 
 begin
     a = Base.Condition()
@@ -44,8 +44,8 @@ if false
     prefixer(prefix, sleep) = `perl -nle '$|=1; print "'$prefix' ", $_; sleep '$sleep';'`
     @test success(pipe(`perl -le '$|=1; for(0..2){ print; sleep 1 }'`,
                        prefixer("A",2) & prefixer("B",2)))
-    @test success(pipe(pipe(`perl -le '$|=1; for(0..2){ print; sleep 1 }'`,
-                            prefixer("X",3) & prefixer("Y",3) & prefixer("Z",3)),
+    @test success(pipe(`perl -le '$|=1; for(0..2){ print; sleep 1 }'`,
+                       prefixer("X",3) & prefixer("Y",3) & prefixer("Z",3),
                        prefixer("A",2) & prefixer("B",2)))
 end