topic Re: ksh? inserting line into files in Operating System - HP-UX

ksh? inserting line into files

Florian Heigl (new acc) — Wed, 02 Feb 2005 22:26:52 GMT

Hi,

I know this is an easy one, and will just say that I caught a flu which makes my head ache a bit too much.

I need to insert a css reference into a LOT of html files.

so far I've thought about
mv foo.html foo.html.bak
while read line < foo.html.bak
do
echo $line >> foo.html
if [ echo $line | grep '' 2>dev/null 1>/dev/null ]
then
echo "$CSS_THINGY" >>foo.html
fi
done

but somehow I get the feeling that this might
blow up or just be a very strange way of doing it.

I'd love some recommendations!

Re: ksh? inserting line into files

Denver Osborn — Wed, 02 Feb 2005 22:47:31 GMT

Permissions of the new foo.html may not match the original... instead of mv, how about cp then null the original file?

cp foo.html foo.html.bak
> foo.html
while read line < foo.html.bak
do
echo $line >> foo.html
if [ echo $line | grep '' 2>dev/null 1>/dev/null ]
then
echo "$CSS_THINGY" >>foo.html
fi
done

-denver

Re: ksh? inserting line into files

Florian Heigl (new acc) — Wed, 02 Feb 2005 22:56:04 GMT

okay :)

I chose mv because it's not updating the original file at all, but forgot about the new file.
then a
cp -p foo.html.bak foo.html and a
> foo.html
would be needed to keep everything in sync.

also, I noticed the if clause must read
if [` echo $line | grep '' 2>dev/null 1>/dev/null `]

I'll try it later, right now I'm just to dizzy.

Re: ksh? inserting line into files

Denver Osborn — Wed, 02 Feb 2005 22:59:16 GMT

same here, it's past my bedtime. I didn't bother to test it before posting... just did a cut/paste to point out cp -vs- mv.

I'm sure one of the perl gurus will wake up and solve this one w/ a few lines of perl script for you.

-denver

Re: ksh? inserting line into files

Florian Heigl (new acc) — Wed, 02 Feb 2005 22:59:37 GMT

I knew I shouldn't trust myself :)

-su[4]: dev/null: cannot create [No such file or directory]
-su[4]: []: not found [No such file or directory]
-su[4]: dev/null: cannot create [No such file or directory]
-su[4]: []: not found [No such file or directory]
-su[4]: dev/null: cannot create [No such file or directory]
-su[4]: []: not found [No such file or directory]
-su[4]: dev/null: cannot create [No such file or directory]
-su[4]: []: not found [No such file or directory]
-su[4]: dev/null: cannot create [No such file or directory]

(see You in 12 hrs :)

Re: ksh? inserting line into files

Biswajit Tripathy — Wed, 02 Feb 2005 23:21:32 GMT

Replace :
--------
if [ echo $line | grep '' 2>dev/null 1>/dev/null ]
then
.... ....
-----------

with :

-------------
echo $line | grep -q ''
if [ $? -eq 0 ]
then
...... ....
-----------

BTW, the error messages printed by your script was
bacause of typo ('dev/null' instead of '/dev/null')

- Biswajit

Re: ksh? inserting line into files

Hein van den Heuvel — Thu, 03 Feb 2005 00:58:22 GMT

required perl alternative:

perl -i -ne 'print; print "css\n" if (/<\/title/)' x.html

If you'd need a line before a marker it reduces to:

perl -i -pe 'print "css\n" if (/<\/title/)' x.html

The "-i" creates a temp file. The alternative is the old
perl -ne 'print; print "css\n" if (/<\/title/)' < x.bak > x.html

you can pull in an shell symbol through $ENV{name}

perl -i -ne 'print; print "$ENV{\"XX\"}\n" if (/<\/title/)' x.tmp

and one of many awk solutions:

awk 'BEGIN {css=ENVIRON["CSS_THINGY"]}{print}/<\/title>/{print css}' x.tmp

CHeers,
Hein.

Re: ksh? inserting line into files

Michael Schulte zur Sur — Thu, 03 Feb 2005 08:20:35 GMT

Hi,

2>dev/null 1>/dev/null
There is a / missing hence the errors.

Secondly, if you run a faulty script twice, you loose your original.

what about
awk '/<\/title>/ {print $0;print "CSS_THINGY";next;}{print $0}' foo.html

greetings,

Michael

Re: ksh? inserting line into files

Florian Heigl (new acc) — Thu, 03 Feb 2005 17:19:40 GMT

Biswajit - thanks for the grep -q :)

And Hein - thank You for trying to build something more reasonable than that 'late night dilemma' I made - I chose Your awk solution, it takes well below a second for 100 files, which is very acceptable!

Michael - You've been right about the fact that I'd lose the originals by every second run. It was no issue because the files will be regenerated quite often but it's well worth noting.

Re: ksh? inserting line into files

Florian Heigl (new acc) — Thu, 03 Feb 2005 17:21:51 GMT

see last posting :)