topic Backslash in SED in Operating System - HP-UX

Backslash in SED

FRED Dennison — Mon, 08 Jan 2001 20:40:14 GMT

I am trying to use SED to alter a variable with forward slashes in it (an omniback session reference "2000/12/31-5"). The aim is to use this variable in another SED statement to subtitute it for another String, but the forward slahes cause problems. I was intending to program in backslashes before each forward slash in the variable, then use the result to replace the relevant strings.

Command 1 = export $SESSION = echo 2000/12/31-5 | sed -e "s/\//\/g" # (Replace / with \/ - doesn't work)

Command 2 = sed -e "s/var1/$SESSION/g" # ($SESSION = result of Command1)

Any ideas?

Re: Backslash in SED

Curtis Larson — Mon, 08 Jan 2001 20:53:03 GMT

it should be :
sed -e 's/\//\\\/g'

or you can use another delimiter:

sed -d 's|/|\\/|g'

Re: Backslash in SED

Curtis Larson — Mon, 08 Jan 2001 20:56:22 GMT

oops that should have been a -e instead of -d:

and, of course, if you use a different delimiter you don't need to backslash your slashes in the substitution

Re: Backslash in SED

James R. Ferguson — Mon, 08 Jan 2001 20:57:31 GMT

Fred:

Try:

# echo 2000/12/31-5 | sed -e "s?/?\\\?g"

...JRF...

Re: Backslash in SED

FRED Dennison — Mon, 08 Jan 2001 23:53:45 GMT

Thanks for your assistance. It's works OK now.

Interesting point; the answers above gives the result I wanted to stdout, but to store it in a variable, I had to put another 3 \ characters in the sed command. End result was

export S2='echo $S1|sed -e "s?/?\\\\\\\/?g"'

with ? as delimeter.

FRED

Re: Backslash in SED

Dan Hetzel — Tue, 09 Jan 2001 10:41:04 GMT

Hi Fred,

The reason why you have to add a couple backslashes when assigning the result to a variable is the following:
Using double quotes doesn't prevent your shell from interpreting the string, you should use simple quotes instead, like in:
a=`echo 2000/12/31-5 | sed -e 's#/#\\\#g'`

This keeps the whole expression 'more readable'. ;-)

Best regards,

Dan

Re: Backslash in SED

Ian_9 — Tue, 09 Jan 2001 15:55:01 GMT

sed uses ed and that states that "s/whatever/something/" can be "s;whatever;something;". IE the "/" is an ed delimiter. Using anything other than "/" usually gets rid of the problems you are having.

Regards
ian