read complete lines in a for loop

[Oliver Charni]

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

[Bill McNAMARA_1]

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

Later,
Bill

[Darrell Allen · Accepted solution]

Hi Oliver,

I prefer a while loop:

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

Darrell

[Justo Exposito]

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.

[S.K. Chan]

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

[Shahul]

Hi

Please try this..I have tested now

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


Best of luck
Shahul

[Steven Sim Kok Leong]

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

[Steven Sim Kok Leong]

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

[A. Clay Stephenson]

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.

[H.Merijn Brand (procura]

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