topic Re: Shell script question in Operating System - HP-UX

Shell script question

Jeff Picton — Mon, 13 Sep 2004 07:28:46 GMT

Hi

I need to create a new file within a shell script so that the new file may be then manipulated. I know the following :-

cat > filename but this hangs. Can anyone suggest another means so that filename may then be copied or moved ?

Thanks

Jeff

Re: Shell script question

Geoff Wild — Mon, 13 Sep 2004 07:32:19 GMT

# setup the log file
LOG=/tmp/some.log
if [ -f $LOG ]
then
mv $LOG $LOG.old
fi
cat /dev/null > $LOG

Rgds...Geoff

Re: Shell script question

RAC_1 — Mon, 13 Sep 2004 07:34:36 GMT

The easiest way I could think is doing something as follows.

touch file_name
echo "something" >> file

Anil

Re: Shell script question

Muthukumar_5 — Mon, 13 Sep 2004 07:36:40 GMT

You can use touch command to create a file. But it will be used to update the file informations.

touch filename

touch filename
By simple you can create as,

> filename

or

cp /dev/null filename

More you can create, file as,

>| filename

Where,

>| used for when the file exists there. By default if you user > filename on

set -o noclobber

> filename

will make error messages for existing files.

So use

>| filename

to avoid error to update informations of file.

REgards
Muthu

Re: Shell script question

John Palmer — Mon, 13 Sep 2004 07:37:13 GMT

Hi Jeff,

'touch filename' will create a file if it doesn't exist already.

Simply '> filename' will create a file and also empty it if it already exists.

If you know what data you want it to contain, you can use cat with a 'here' document as follows:
cat > filename << EOF
your
data
EOF

EOF is an arbitrary terminator, you can pretty much use whatever you like. See man sh-posix for full details.

Regards,
John

Re: Shell script question

Muthukumar_5 — Mon, 13 Sep 2004 07:41:15 GMT

why are you trying cat > filename there,

It may be used as,

cat filename > newfilename
cat filename >| newfilename (noclobber mode)

or

cat filename >> newfilename

It will append content.

Else as,

echo "test" | cat - > filename

- --> collect all stdoutput message which got from pipe redirection.