topic Re: read complete lines in a for loop in Operating System - HP-UX

read complete lines in a for loop

Oliver Charni — Mon, 10 Jun 2002 12:53:16 GMT

hi all!

Can anyone help me out here, I need to read completes Lines of a File in a for loop.
for i in //filename//
and i is supposed to be the first, second etc. line of that file.

Anyone got an Idea how I could do that ?

kind regards
Oliver

Re: read complete lines in a for loop

Bill McNAMARA_1 — Mon, 10 Jun 2002 12:54:49 GMT

for i in $(cat filename)
do
echo $i
done

Later,
Bill

Re: read complete lines in a for loop

Darrell Allen — Mon, 10 Jun 2002 13:04:02 GMT

Hi Oliver,

I prefer a while loop:

while read line
do
echo "$line"
done
Quoting $line maintains spacing.

Darrell

Re: read complete lines in a for loop

Justo Exposito — Mon, 10 Jun 2002 13:04:11 GMT

Hi Oliver,

You must beware with the spaces or tabs character into the file, this is because the for structure takes this as a separator.

If you have spaces in your file you must replace (use sed) by a different character in order to use the whole line as one parameter.

Hope this helps,

Justo.

Re: read complete lines in a for loop

S.K. Chan — Mon, 10 Jun 2002 13:08:48 GMT

With the "while" loop you have more control. For example reading /etc/passwd using ":" as field separator.

IFS=:
exec 0while read -r Name Pass Uid Gid Comm Home Shell
do
print "$Name $Uid $Gid"
done

Re: read complete lines in a for loop

Shahul — Mon, 10 Jun 2002 13:33:03 GMT

Hi

Please try this..I have tested now

for i in "`cat file`"
do
echo "$i"
done

Best of luck
Shahul

Re: read complete lines in a for loop

Steven Sim Kok Leong — Mon, 10 Jun 2002 14:39:43 GMT

Hi,

Here's another method (takes care of spaces and tabs):

#!/usr/bin/sh

inc=1
total=`cat $1 | wc -l`

while [ "$inc" -le "$total" ]
do
tail -$inc $1 | head -1
inc=`expr $inc + 1`
done

Hope this helps. Regards.

Steven Sim Kok Leong

Re: read complete lines in a for loop

Steven Sim Kok Leong — Mon, 10 Jun 2002 14:49:19 GMT

Hi,

Sorry, made a typo (swapped the head and tail). Should be:

#!/usr/bin/sh

inc=1
total=`cat $1 | wc -l`

while [ "$inc" -le "$total" ]
do
head -$inc $1 | tail -1
inc=`expr $inc + 1`
done

Hope this helps. Regards.

Steven Sim Kok Leong

Re: read complete lines in a for loop

A. Clay Stephenson — Mon, 10 Jun 2002 14:54:07 GMT

Here is yet another (and the really classic) method - reading using a file descriptor:

INFILE="myfilename"

exec 9<${INFILE}
X=$(line <&9)
STAT=$?
while [ ${STAT} -eq 0 ]
do
echo "${X}"
X=$(line <&9)
STAT=$?
done

Reading using a file descriptor reads the lines sequentially.

Re: read complete lines in a for loop

H.Merijn Brand (procura — Mon, 10 Jun 2002 15:22:20 GMT

Read file by line and print;

# perl -pe 1 file

Read file by line and insert line number at front

# perl -pe 's/^/$. /' file

Read file by line and make it useful (if the content is possitive)

# perl -pe 's/ms-?dos/hp-ux/ig' file