I have the following file (records from db) and I need to retrieve in another file only two variables and their values. I have a command but works only for one value.
grep ^mob: R25-subs.ldi | sed 's/mob: //' | sort | uniq >text_output

Can someone please help me?
dn: cn=30693xxxxxxx,ou=sub,o=company
mob: x_var
pref: aaaaaaaa
sn: 30693xxxxxxxxxxx
userpassword: xxxxxxxxxx
allowmt: true
searchon: mms3069xxxxxxxx
searchon: mars30693xxxxxxx
allowmo: true
objectclass: xxxx
objectclass: xxxx
objectclass: xxxx
objectclass: xxxx
objectclass: xxxx
objectclass: xxxx
uid: 30693xxxxxx
cn: 30693xxxxxx
community: xxxxxx
orclguid: xxxxxxxxxxxxxxxxxxxx
creatorsname: cn=xxxxxxxx
modifiersname: cn=xxxxxxxx
createtimestamp: 2003xxxxxxxx
modifytimestamp: 2003xxxxxxxx

dn: cn=30693xxxxxxxx,ou=subscribers,o=company
mob: y_var
sn: 30693xxxxxxx
userpassword: xxxxxxxxxxxx
allowmt: true
searchon: mms30693xxxxxxx
searchon: mars3069xxxxxxx
allowmo: true
objectclass: xxxxx
objectclass: xxxxx
objectclass: xxxxx
objectclass: xxxxx
objectclass: xxxxx
objectclass: xxxxx
uid: 30693xxxxxx
cn: 30693xxxxxx
community: xxxxxx
orclguid: xxxxxxxxxxxxxxxxxxxxxxxxxx
creatorsname: cn=xxxxxxx
modifiersname: cn=xxxxxxx
createtimestamp: 20030212073811
modifytimestamp: 20040309041005
pref: bbbbbbbbb

...etc
How can I have an text output from the above block as:
x_var aaaaaaa
y_var bbbbbbb

or something like that
??????

Try..

awk '
/^mob/ { m = $2 }
/^pref/ { print m, $2 }
' infile

Tested...

x_var aaaaaaaa
y_var bbbbbbbbb

Or try using various utilities to get what you want...

$ egrep '^mob|^pref' infile
mob: x_var
pref: aaaaaaaa
mob: y_var
pref: bbbbbbbbb
$ egrep '^mob|^pref' infile | cut -d' ' -f2
x_var
aaaaaaaa
y_var
bbbbbbbbb
$ egrep '^mob|^pref' infile | cut -d' ' -f2 | paste -d' ' - -
x_var aaaaaaaa
y_var bbbbbbbbb

thanks dudes, it was very helpful!!!

I did the following:
egrep 'mob:|pref:' filename

the only problem (minor) was that there was an output like difficult to follow like
mob=xxxx
pref=yyyy
mob=xxxx
pref=yyyy...

Anyway now I 'll try your ways...