kano ta prota mou bimata....boithiste me parakalo

[Giorgos Keramidas]

On 2003-03-30 15:15, Aleksandros Paleos <apalaios at cs.teiath.gr> wrote:
> Xaireto prospatho na matho na ftiaxno kapoia script files kai exo
> polla problimata , skeftika na apeythyntho se esas gia na me
> boithisete . Ean sas fainontai polles oi apories mou apantiste sas
> parakalo se opoies mporeite...
> Exyaristo poly
>
> Exo faei olo to proi prospathontas na grapso ena script file to
> opoio na antistrefei ta periexomena enos arxeiou kai na ta
> apothikeyei se ena allo Kateliksa se ayto to script file
>
>
> i=100  #tha prepei to arxeio dystyxos me mikrotero megethos apo 100 grammes
> while (test  $i -gt 1)
> do
>         #echo $i
>         i=`  expr $i - 1`
>         tail +$i $1|head -1 >>$2  #epilegete kathe fora mono mia grammi
> done

PROS THEOU ANTHROPE MOU!  Oxi scripts se csh...
http://www.faqs.org/faqs/unix-faq/shell/csh-whynot/

Gia na kaneis auto pou les parapanw einai kati san auto to mikro
bash(1) script:

	count=$( wc -l $filename | awk '{print $1}' )
	for line in $( jot "${count}" "${count}" 1 ) ; do
		head -"${count}" "${filename}" | tail -1
	done

> Opos mporeite na deite ektelo mia epanalipsi i opoia kathe fora
> epilegei mia grammi ksekinontas apo 100 pros ta pano apo ti thesi
> 100 kai paei pros to 1.  Oso kai ean fainetai parakseno ayto
> douleyei giati ean to arxeio mas den exei 100 grammes tote to tail
> +100 den epistrefei tipota...

Logiko :)

> Bebaia prospatho na bro enan tropo na metrao tis grammes tou protoy
> arxeiou gia na ekteleitai mono toses fores i epanalipsi...

	count=$( wc -l filename | awk '{print $1}' )

> prospathisa na grapso kati se
> a=` expr wc -l file`
> alla den mou doulepse...

Trexeis to `expr' me parametrous:

	expr wc -l file

Otidhpote einai se `...` backquotes, mporeis na to dokimaseis kai
ksexorista sto command line sou:

	$ expr wc -l .procmailrc
	expr: syntax error

Ara gi auto den sou paizei.  Auto pou thes einai to expr na dei sto
command line tou to APOTELESMA tou wc -l, dhladh kati san:

	$ expr `wc -l .procmailrc`

Auto den einai polu sosto omws, afou pali den petuxainei.  Giati?

	$ expr `wc -l .procmailrc`
	expr: syntax error

As doume ti bgazei to `wc -l':

	$ wc -l .procmailrc
	     198 .procmailrc

Hmmmm, logiko loipon pou apotugxanei to expr, afou to trexeis san:

	$ expr      198 .procmailrc

> Ara me poion tropo mporo na metriso tis grammes enos arxeiou?

Me wc -l.  Auto pou thes einai to apotelesma, kai malista mono ton
arithmo na to anatheseis se mia metablhth.

	$ wc -l .procmailrc
	     198 .procmailrc

	$ wc -l .procmailrc | awk '{print $1}'
	198

	$ count=` wc -l .procmailrc | awk '{print $1}' `

	$  echo $count
	198

	$ unset count

> Yparxei parametros stin entoli ls pou na mou deixnei mono ta files?

Oxi, alla panta mporeis na paikseis me th grep kai thn awk:

	$ ls -l /tmp
	total 16
	-rw-------  1 giorgos  wheel  - 3352 Mar 30 21:28 #mutt-gothmog-2167-24#
	-rw-rw-rw-  1 giorgos  wheel  -    0 Mar 30 18:47 grkbd.lock
	-rw-------  1 giorgos  wheel  - 1991 Mar 30 21:18 mutt-gothmog-2167-24
	drwxr-xr-x  4 root     wheel  -  512 Mar 30 18:48 screens
	drwx------  2 giorgos  wheel  -  512 Mar 30 18:47 ssh-d00gBobE

	$ ls -l /tmp | grep '^-'
	-rw-------  1 giorgos  wheel  - 3352 Mar 30 21:28 #mutt-gothmog-2167-24#
	-rw-rw-rw-  1 giorgos  wheel  -    0 Mar 30 18:47 grkbd.lock
	-rw-------  1 giorgos  wheel  - 1991 Mar 30 21:18 mutt-gothmog-2167-24

	$ ls -l /tmp | grep '^-' | awk '{print $10}'
	#mutt-gothmog-2167-24#
	grkbd.lock
	mutt-gothmog-2167-24

> Prospatho na grapso ena programma pou na emfanizei ta periexomena
> enos arxeiou mono ean to periexomeno toy einai megalytero apo 10
> grammes

	[ $(wc -l $filename) -gt 10 ] && cat $filename

> Episis psaxno na bro enan tropo gia to pos mporo na emfanizo mono ta
> login names kai ta home direcotries ton xriston pou exoyn syndethei
> sto sistima mou kapia apopsi?

Prepei epeigontws na deis pos paizei h awk:

	$ awk -F: '{print $1,$6}' < /etc/passwd
	root /root
	sysop /root
	daemon /root
	operator /
	bin /
	...

> Kai telos prospatho na bro enan tropo na stelno ena minima se osous
> xristes exoun kanei log in

Panta uparxei h entolh who:

	$ who
	giorgos          ttyv0    Mar 30 18:47
	root             ttyp1    Mar 30 19:12 (:0:S.0)

	$ who | awk '{print $1}'
	giorgos
	root

	$ for user in ` who | awk '{print $1}' `; do \
	      echo hello $user ; done
	hello giorgos
	hello root

- Giorgos