#!/bin/bash

 # Copyright (c) 2004 Matthias S. Benkmann <article AT winterdrache DOT de>

 # You may do everything with this code except misrepresent its origin.

 # PROVIDED `AS IS' WITH ABSOLUTELY NO WARRANTY OF ANY KIND!

 

 #The following list should contain the mount points of all filesystems

 #that are to be scanned as a space-separated list within parentheses. 

 #/ will usually be in this list and if you have /usr

 #on a separate partition, it will also be in this list. 

 #Mount points whose filesystems are special, such as procfs or sysfs must

 #not be in this list. While a simple find on those special filesystems should 

 #be harmless, operations such as "-exec grep something" are NOT SAFE and may 

 #have HARMFUL SIDE-EFFECTS, especially when performed as root. 

 fs_to_scan=(/)

 

 #Files with a path prefix found in the following list are ignored. As the

 #main function of this script is to help you find files that contain

 #hardwired paths to /tools or other unwanted references to

 #your build system, you will usually prune any directories that don't contain

 #files of interest, such as /tools (whose files naturally refer to /tools)

 #and your package users' home directories (which may also test positive if

 #you have unpacked and configured sources lying around).

 #NOTE: The LFS-6.0 book uses a ramfs mounted on /dev and with that setup

 #/dev does not need to be in the prune list. But since there is no requirement

 #that /dev have its on filesystem it's better to prune it explicitly.

 prune_prefixes=(/home /usr/src /dev /tools) #NO TRAILING SLASHES!!!

 

 if [ $# -lt 1 -o "$1" = "--help" ]; then

   echo 1>&2 

   echo 1>&2 'USAGE: '"${0##*/}"' <grep-commands>'

   echo 1>&2 

   echo 1>&2 '  grep -l <grep-commands> -- <file>'

   echo 1>&2 '  will be executed for each *regular file* <file>'

   echo 1>&2 '  ATTENTION! If you override the -l switch with a switch that makes grep'

   echo 1>&2 '  output all individual matches rather than just the matching files,'

   echo 1>&2 '  then DO NOT redirect output to a file that is in a directory that will be'

   echo 1>&2 '  scanned, or you risk creating an endless loop that will cause your'

   echo 1>&2 '  output file to grow till your disk is full.'

   echo 1>&2 

   exit 1

 fi

 

 #suppress ugly debug output from shell

 trap ':' SIGPIPE

 

 #construct find commands that match the prune_prefixes. Each prefix will be

 #matched as -path <prefix> -or -path <prefix>/*

 #so that the directory itself and all subdirectories are matched.

 y=(\( -false)

 for ((i=0; $i<${#prune_prefixes[@]}; i=$i+1)) 

 do

   y[${#y[@]}]='-or'

   y[${#y[@]}]=-path

   y[${#y[@]}]="${prune_prefixes[$i]}"

   y[${#y[@]}]='-or'

   y[${#y[@]}]=-path

   y[${#y[@]}]="${prune_prefixes[$i]}/*"

 done

 y[${#y[@]}]=')'

 

 cmd_pre=(-type f -exec grep -l)

 cmd_post=(-- {} \;)

 

 #In the following find command, the part

 # -not ( ( "${y[@]}" -prune ) -or "${y[@]}" )

 #is responsible for preventing the files that match prune_prefixes from

 #being processed. The 2nd "${y[@]}" may seem redundant, but it isn't, because

 #-prune has no effect and is always false when -depth is used (which someone

 #might do in the future).

 #The -true before "$@" ensures that -depth can be passed as 1st parameter

 #of $cmd_pre (should someone change it in the future).

 find "${fs_to_scan[@]}" -xdev -noleaf \

      -not \( \( "${y[@]}" -prune \) -or "${y[@]}" \) \

      -and \( -true "${cmd_pre[@]}" "$@" "${cmd_post[@]}" \)