ls and egrep together

Shell Programming and Scripting
1

Hello,
Why is this not returning files containing the string in the var $files?

files=`ls /dir1/dir_level2/dir_level3 | egrep "catch \["`

files=`ls /dir1/dir_level2/dir_level3` this by itself returns a list of files which I thought could be sent through grep or egrep to look for matches.

Can you help me understand?

Thanks.

2

Does ls /dir1/dir_level2/dir_level3 | egrep "catch \[" return something?

3

It does not return anything, and I know there are matches for this search .....
Thanks.

4

The syntax is:

egrep "catch \[" /dir1/dir_level2/dir_level3/*

Regards

5

Shouldn't these be equivalent? Yet they are not.
Can anyone explain? thanks.

files=`ls /dir1/dir_level2/dir_level3 | egrep "catch \["`
or even
files=`ls /dir1/dir_level2/dir_level3/* | egrep "catch \["`

files=`egrep "catch \[" /dir1/dir_level2/dir_level3/*`

6

No, they are not. These commands search for a pattern in the filenames:

files=`ls /dir1/dir_level2/dir_level3 | egrep "catch \["`
files=`ls /dir1/dir_level2/dir_level3/* | egrep "catch \["`

While this command search for a pattern in the files:

files=`egrep "catch \[" /dir1/dir_level2/dir_level3/*`

Regards