On 16:38 23 Sep 2002, Spanke, Alexander <[EMAIL PROTECTED]> wrote:
| Hi again,
|
| How can i count the lines of a text file and store it in a variable. But i
| should use the bash, so no perl, python script should it be.
|
| Now i use
| wc -l < file.txt | read dummy
|
| But it doesn't work :(
Others have already shown you the
lines=`wc ......`
incantation, but not explained why your method was failing.
In your example, the "read" is happening in a subshell (because all
processes in a pipeline are subprocesses), and variables are not shared
between processes, merely passes from the partent to the child when the
child is made.
So this:
a=1
echo 2 | read a
echo $a
will print "1". Compare this:
a=1
echo 2 | { read a; echo $a; }
echo $a
which will print "2" from the first echo, which is in the same shell
as the "read" (i.e. the {....} part) and "1" from the second echo as in
the first example.
--
Cameron Simpson, DoD#743 [EMAIL PROTECTED] http://www.zip.com.au/~cs/
He's silly and he's ignorant, but he's got guts, and guts is enough.
- Sgt. Hartmann
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