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variables in sed


 
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# 1  
Old 01-02-2002
variables in sed

when i do something like substituting a particular thing with a system variable, i am unable to do that expect the varible name getting into that.

for ex.. i tried,

sed -e 's/date/`date`/g' <if >of

but i got date replaced with "`date`" and not with the actual date ..
same case happened with a variable $var.

Can I know where I go wrong?

Thanks
sskb
# 2  
Old 01-03-2002
It's the single-quotes surrounding the s//g statement. They are there to make sure nothing sent to sed is interpretted by the shell first, and that includes back-quotes.
# 3  
Old 01-03-2002
well, see the example..

----------------------------

sh-2.05$ cat file

date

sh-2.05$ sed "s#date#`date`#" file

Thu Jan 3 20:39:08 JAVT 2002

sh-2.05$

----------------------------

i guess that's what you mean.
# 4  
Old 01-03-2002
Thanks LivinFree and Negative,
I got that and I wish to know more about these chatacterisations with sed. I could not find much info on

man sed

thanks again
Smilie
sskb
# 5  
Old 01-03-2002
Well, okay.. Now for completing your HAPPINESS :)

please visit this URL, http://www.dbnet.ece.ntua.gr/~george/sed/1liners.html, i promise it will give you more info about sed.

Peace,
# 6  
Old 08-31-2007
you can use double quotes instead of single quotes.. while using single quotes sed wont substitute value of variables, but using double quotes will substitute value..

example: sed "s/$var/" filename

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