An advanced Write node for Nuke where you can define certain path fragments which are combined to the final path via expressions.

CK_Write.tcl

set cut_paste_input [stack 0]
version 10.5 v1
push $cut_paste_input
Write {
file "\[string trimright \[value projectroot] \\\\/]/\[string trimright \[value outputfolder] \\\\/]/\[string trimright \[value shot] \\\\/]/\[string trimright \[value task] \\\\/]/\[if \{\[value enable_cache]\} \{return \[value cachefolder]/\[string trimright \[value cache] \\\\/]/\}]\[if \{\[value file_type] == \"mov\"\} \{return \[string trimright \[value outputfilename] \\\\/].\[value file_type]\} \{return \[string trimright \[value outputfilename] \\\\/]/\[string trimright \[value outputfilename] \\\\/]\[value padding].\[value file_type]\}]"
proxy "\[string trimright \[value projectroot] \\\\/]/\[string trimright \[value outputfolder] \\\\/]/\[string trimright \[value shot] \\\\/]/\[string trimright \[value task] \\\\/]/\[if \{\[value enable_cache]\} \{return \[value cachefolder]/\[string trimright \[value cache] \\\\/]/\}]\[if \{\[value file_type] == \"mov\"\} \{return \[string trimright \[value outputfilename] \\\\/]\[value proxy_indicator].\[value file_type]\} \{return \[string trimright \[value outputfilename] \\\\/]\[value proxy_indicator]/\[string trimright \[value outputfilename] \\\\/]\[value proxy_indicator]\[value padding].\[value file_type]\}]"
file_type exr
create_directories true
name CK_Write1
label "\[if \{\[value showpath]\} \{return \[expr \{\[value root.proxy]\} ? \{\[value proxy]\} : \{\[value file]\}]\}]\n"
addUserKnob {20 PathFragments}
addUserKnob {2 projectroot}
projectroot "\[value project_directory]"
addUserKnob {1 outputfolder}
outputfolder 04_renders/010
addUserKnob {1 shot}
shot 000_000
addUserKnob {1 task}
task compositing
addUserKnob {1 cachefolder l cache}
cachefolder cache
addUserKnob {1 cache l / -STARTLINE}
cache denoise
addUserKnob {6 enable_cache l enable -STARTLINE}
addUserKnob {1 outputfilename}
outputfilename "\[file root \[file tail \[value root.name]]]"
addUserKnob {1 padding}
padding _####
addUserKnob {1 proxy_indicator l proxy}
proxy_indicator _proxy
addUserKnob {26 ""}
addUserKnob {22 copyfileoutputpath l "Copy file output path" T "from PySide import QtGui\n\nclipboard = QtGui.QApplication.clipboard()\npath = nuke.thisNode()\['file'].getEvaluatedValue()\nclipboard.setText(path)" +STARTLINE}
addUserKnob {22 copyproxyoutputpath l "Copy proxy output path" -STARTLINE T "from PySide import QtGui\n\nclipboard = QtGui.QApplication.clipboard()\npath = nuke.thisNode()\['proxy'].getEvaluatedValue()\nclipboard.setText(path)"}
addUserKnob {6 showpath l "Show path in label" +STARTLINE}
}