Hi,
Could someone please tell me how to set the result of a pipeline as a new variable

e.g cat file | cmd to remove every character but the first letter | ?

what do I need to put to assign the outcome (a single letter in this case) to a variable?

Any help would be greatly appreciated.

Use command substitution:

For bourne shell

char=`cmd|cmd|cmd` # back-tics, not single quotes

For korn and bash:

char=$(cmd|cmd|cmd)

thats great -thanks very much for your help

Unfortunately I have another question...

if I have a file that contains variable information

e.g file

erx2=yes
gex9=yes

how can I use these later in the script that has created the file? at the moment and am using a very dodgy 'if' statement as follows

var=`grep erx2 file`
if [ $var="erx2=yes" ]
then var=yes
else
var=no
fi

this always sets var=yes
even of there is no line in file that matches the grep on the first line.

Any help would be greatly appreciated.

Relational operators need to be surrounded by white space, same as the brackets. So your command

if [ $var="erx2=yes" ]

just needs to be

if [ $var = "erx2=yes" ]

As it was, you had a single operand - a mixture of a variable and literals - and it will test true if the string is not null, which of course it would always be not null due to the literals.

And you might find the following helpful ...

eval `grep erx2 file`
echo $erx2
yes

The grep finds (or maybe not) the erx2=yes line, and that feeds into the eval command which evaluates it and sets the variable. You can then test for the variable's content in the normal fashion, but since it may not exist, make sure you surround with double_quotes to avoid a syntax error:

if [ "$erx2" = yes ]
then echo yep
else echo nope
fi

you can do a count on the match

#!/bin/sh
if [ `grep -c "erx2=yes" file3` -gt 0 ]
then
var=yes
else
var=no
fi
echo $var

Regards,
Devaraj Takhellambam

I went with the eval method which worked prefectly.
Thanks Nails, James Booth and Devaraj you have been extremely helpful.