topic Re: Shell programming: Search a blank in Operating System - HP-UX

Shell programming: Search a blank

Miguel Cuesta — Mon, 06 Aug 2001 07:42:42 GMT

Hi!

I'm creating a shell script, and I want to execute a command only if there is a blank in ${FILE}.

How could I carry it out?

if _?_?_?_ then
[command]
fi

Thank you very much.

Re: Shell programming: Search a blank

Robin Wakefield — Mon, 06 Aug 2001 07:55:14 GMT

If, by blank, you mean the file is empty, then:

if ! [ -s $FILE ] ; then
...
fi

but if you mean a single space as the only line, then:

if [ `cat $FILE | wc -w` -eq 0 ] ; then
...
fi

could be one way to do it.

Robin

Re: Shell programming: Search a blank

Stefan Schulz — Mon, 06 Aug 2001 08:15:11 GMT

If you are really looking for a blank (" ") and not a blank file or a blank line in this file you could use:

if [ `grep -c " " $FILE`] ; then
...
fi

Hope this helps

Regards Stefan

Re: Shell programming: Search a blank

Praveen Bezawada — Mon, 06 Aug 2001 08:26:45 GMT

Hi
If you are looking for a blank line in a file

while read each_line;do
echo $each_line | grep " " > /dev/null
if [ $? -eq 0 ];then
echo $each_line
.
.
.
fi
done
where a.lst in the input file

..PRB...

Re: Shell programming: Search a blank

Uffe Gavnholt_1 — Mon, 06 Aug 2001 08:26:51 GMT

And finally if you need to search for a blank in the file name, try this:

if
echo $FILE | grep " "
then
...
fi

Re: Shell programming: Search a blank

Miguel Cuesta — Mon, 06 Aug 2001 09:13:52 GMT

I meant 'a blank in the __file name__'

Thank you.

Re: Shell programming: Search a blank

Miguel Cuesta — Mon, 06 Aug 2001 09:24:12 GMT

Using Uffe's script, I get this message:

./myscript.sh[43]: test: A ] character is missing.
grep: can't open ]

Re: Shell programming: Search a blank

Dave Kelly_1 — Mon, 06 Aug 2001 09:40:52 GMT

You can use:

if [ `echo $FILE | wc -w` -gt 1 ]
then
commands
fi

Re: Shell programming: Search a blank

Joseph Chakkery — Mon, 06 Aug 2001 09:42:02 GMT

Hello,

Try this one.

FILE="File Name" #Let's say var is like this.
echo $FILE|grep " " >/dev/null
if [ $? -ne 0 ]
then
echo " There is sapce" #U can run ur script here.
else
echo "No space"
fi

Hope this may help u.

Re: Shell programming: Search a blank

Wodisch — Mon, 06 Aug 2001 10:42:54 GMT

Hello Miguel,

first you will have to *quote* anyway ;-)
Then, if you are looking for the values of "${FILE}" as
a variable, test it like this:
if [ "${FILE}" = " " ]
then echo "Bingo - a space only"
fi

Or you can insert some (almost) arbitrary characters
for readability:
if [ "x${FILE}x" = "x x" ]
then echo "Bingo - a space only"
fi

But if you are checking wether there is file with the name
in "${FILE}", and this only contains a single space, you
will have to do something like:
if [ "$(wc -c ${FILE})" -eq 1 ]
then if [ "$(cat ${FILE})" = " " ]
then echo Bingo - the files contains only a space
else echo file is only one char in size but not a space
fi
fi

HTH,
Wodisch

PS: You could use "perl", where you have direct access
to the file's attributes, like size, and where file-
handling is pretty simple...

Re: Shell programming: Search a blank

Magdi KAMAL — Mon, 06 Aug 2001 10:50:48 GMT

Hi Miguel,

# The argument for the grep is one blank
echo $fileName ? grep " " > /dev/null
if [[ $? = 0 ]]
then
echo " File name contains at least one blank"
else
echo " File name does not contains at least one blank"
fi

Magdi

Re: Shell programming: Search a blank

Curtis Larson_1 — Mon, 06 Aug 2001 17:06:06 GMT

in the ksh:

if [[ "$file" = *+( )* ]] then

or for other white space character also

if [[ "$file" = *+([:space:])* ]] then

Re: Shell programming: Search a blank

Phil Squire — Tue, 07 Aug 2001 08:35:02 GMT

You're always going to stuggle testing for spaces in shell because it's a delimeter. What about awk?

echo "$file" | awk 'BEGIN {FS=""} / / {print "*" }'

Will print an asterix if $file contains one or more spaces, including leading and trailing spaces.

Hope this helps.
Phil

Re: Shell programming: Search a blank

David G Ledger — Thu, 09 Aug 2001 12:57:56 GMT

If the variable FILE is to be tested for an embedded blank:

set -A temp $FILE
[ ${#temp[*]} -gt 0 ] && echo "$FILE has a blank"

All shell builtin commands - no fork/exec

David

Re: Shell programming: Search a blank

Tapani Tarvainen — Sun, 12 Aug 2001 16:16:17 GMT

case "$FILE" in
*' '*) ... ;;
esac

Simple, efficient, works in every sh-type shell from original Bourne up.

Re: Shell programming: Search a blank

David G Ledger — Tue, 14 Aug 2001 11:52:54 GMT

Of course I meant

[ ${#temp[*]} -gt 1 ] && echo "$FILE has a blank"