views:

262

answers:

2

Perhaps easiest to explain with an example:

$ echo '\&|'
\&|
$ echo '\&|' | while read in; do echo "$in"; done
&|

It seems that the "read" command is interpreting the slashes in the input as escapes and is removing them. I need to process a file line by line without changing its contents and I'm not sure how to stop read from being smart here. Any ideas?

+1  A: 

Accrding to: http://www.vias.org/linux-knowhow/bbg_sect_08_02_01.html :

-r
If this option is given, backslash does not act as an escape character. The backslash is considered to be part of the line. In particular, a backslash-newline pair may not be used as a line continuation.

It works on my machine.

$ echo '\&|' | while read -r in; do echo "$in"; done
\&|
Zsolt Botykai
Awesome, thanks! I feel dumb for not having found the documentation for this, but it's one of those things that's hard to search for because the terms are rather generic :(
Jeremy Huiskamp
Btw, what shell are you using that does not require the -r? I'm using bash.
Jeremy Huiskamp
Sorry, I was miss used copy paste. Editing ...
Zsolt Botykai
+1  A: 

Use read -r, as per http://www.ss64.com/bash/read.html:

-r
If this option is given, backslash does not act as an escape character.

Alex Martelli
Thanks Alex. Unfortunately I can only mark one as the answer and Zsolt beat you by a mere minute :)
Jeremy Huiskamp
Heh, I know, SO's a 100-meters race for most questions!-)
Alex Martelli