sed replacing patterns with back quoted command

rattlesnakejoe · 11-18-2009, 07:05 AM

Hi,

I have n number of files by name something*.py...i want to replace in all the *.py files, a pattern "1r1z-a" by the last line of its own file

thus, i wrote this sed script

for i in *.py; do sed 's:1r1z-a:'`tail -1 $i`':g' $i; done

But this is not working, "sed: -e expression #1, char 15: unterminated `s' command" is the error message

Plz help

indiajoe · 11-18-2009, 07:32 AM

Hi
Use double quotes (") instead of (')

Code:

for i in *.py; do sed "s:1r1z-a:`tail -1 $i`:g" $i; done

-Cheers
indiajoe

pixellany · 11-18-2009, 09:12 AM

Note that back-tics are deprecated----the preferred construct is $(command)

Quoting:

' is the hard quote---it stops the shell from action on anything inside.

" is the soft quote---allows the shell to act on specific things--most notably expanding a variable--eg $varname