[mdlug] UNIX tips: Learn 10 good UNIX usage habits

[Robert Citek]

On Sun, Mar 9, 2008 at 11:41 PM, Robert Meier <eaglecoach at wwnet.com> wrote:
>  I posted some suggestions to IBM.
>  I included also the conflict between xargs (hint 8)
>  which splits filenames with spaces and quoting (hint 4)
>  which maintains filenames.
>  I suggested using find ... | while read f; do ... "$f" ...; done
>  as more portable, flexible, and less error prone.

Alternatively, you can use the -print0 option to find and the -0
option to xargs.  Perhaps not as portable, but nevertheless useful.

As for the piping cat, I take that rule with a grain of salt.  For
instance, when I'm building up a series of command, I'll often start
with head or grep or similar to pare down date in a largefile.  Then
once I'm confident the pipeline will work, I'll substitute cat.  To
borrow the example on the page, this command:

$ head tmp/a/longfile.txt | grep and

may become this:

$ grep foo tmp/a/longfile.txt | grep and

before it becomes this:

$ cat tmp/a/longfile.txt | grep and

Another reason is that some commands generate different output when
piped vs. when used as arguments.  For example, contrast the output of
these commands:

$ cat /etc/passwd /etc/group | wc -l
$ wc -l /etc/passwd /etc/group

and these:

$ cat /etc/passwd /etc/group | grep root
$ grep root /etc/passwd /etc/group

Regards,
- Robert