Rejecting files with Windows line endings using Perforce triggers

Using Perforce, I'd like to be able to reject submits which contain files with Windows line endings (\r\n IIRC, maybe just \r anywhere as really we only want files with Unix 开发者_JS百科line endings).

Rather than dos2unix incoming files or similar, to help track down instances where users attempt to submit files with Windows line endings, I'd like to add a trigger to reject text submissions which contain files with non-Unix line endings.

Could someone demonstrate how the trigger itself could be written, perhaps with bash or python?

Thanks

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Here's the minimal edit I can thing of for the bash example found in the p4 docs:

#!/bin/sh
# Set target string, files to search, location of p4 executable...
TARGET='\r\n'
DEPOT_PATH="//depot/src/..."
CHANGE=$1
P4CMD="/usr/local/bin/p4 -p 1666 -c copychecker"
XIT=0
echo ""
# For each file, strip off #version and other non-filename info
# Use sed to swap spaces w/"%" to obtain single arguments for "for"
for FILE in `$P4CMD files $DEPOT_PATH@=$CHANGE | \
  sed -e 's/\(.*\)\#[0-9]* - .*$/\1/' -e 's/ /%/g'`
do
  # Undo the replacement to obtain filename...
  FILE="`echo $FILE | sed -e 's/%/ /g'`"
# ...and use @= specifier to access file contents:
  # p4 print -q //depot/src/file.c@=12345
  if $P4CMD print -q "$FILE@=$CHANGE" | fgrep "$TARGET" > /dev/null
  then 
      echo "Submit fails: '$TARGET' not found in $FILE"
      XIT=1
  else
      echo ""

  fi
done
exit $XIT

The original example fails if the target is missing, this one fails if it's present -- just switching the then and else branches of the if. You could edit it further of course (e.g. giving grep, or fgrep, the -q flag to suppress output, if your grep supports it as e.g. GNU's does).