Shell Programming and Scripting

find . | xargs grep <string1>

find . -type f| xargs sed -i 's/old/new/g'

#/bin/ksh
for k in `find ./ -type f| xargs grep oldstring
do
   filename=`echo $k | cut -d ":" -f1`
   sed 's/oldstring/newstring/g' $filename >${filename}.bk
   mv ${filename}.bk ${filename}
done

#/bin/ksh             # Missing ! after #
for k in `find ./ -type f| xargs grep oldstring  # No closing backquote, and expect an Arg list too long error
do
   filename=`echo $k | cut -d ":" -f1`  # not sure why this is needed
   sed 's/oldstring/newstring/g' $filename >${filename}.bk
   mv ${filename}.bk ${filename}  # This is dangerous
done

find . -type -f | while read FILE; do
  sed "s/oldstring/newstring/g" $FILE > $FILE.new
  cp -f $FILE.new $FILE && rm $FILE.new
done

# This is dangerous.  Suppose your "sed" updates an important system file...
$ ls -l rc.tcpip
-rwxrwxr--    1 root     system         6610 Oct 23 09:33 rc.tcpip
 
$ sed "s/old/new/g" rc.tcpip > rc.tcpip.new
 
$ ls -l rc.tcpip.new
-rw-r--r--    1 root     system         6610 Nov 3 10:49 rc.tcpip.new
 
$ mv rc.tcpip.new rc.tcpip
 
$ ls -l rc.tcpip
-rw-r--r--    1 root     system         6610 Nov 3 10:49 rc.tcpip

filename=`echo $k | cut -d ":" -f1`

==> find . -type f | xargs grep hello 
./dir1/file1:hello
./dir1/file2:hello
./dir1/dir2/file4:hello
./dir1/dir2/file5:hello