get the data in a file into single string - UNIX for Dummies Questions & Answers

i.scientist · #1 06-13-2008

Hello everyone !

I need to get the data in a file into a string.
file1
1
2
3
4
5

I need to write a script where the file1 info is stored in a string (say variable s). So the output should be
1,2,3,4,5 or (1,2,3,4,5)
If i say
echo $s or print $s
output should be
1,2,3,4,5
or
(1,2,3,4,5)

Is this possible ? let me know what changes I need to do in the following script

while read file1
do
var=`echo $file1`
temp=`echo $temp","$var"`
echo $temp
done<file1

i.scientist · #2 06-13-2008

temp=`cat file1.dat | sed -n 1p`
while read value
do
var=`echo $value`
if [[ $var -ne "" && $var != $temp ]]
then
temp=`echo $temp,$var`
fi
done<file1.dat
echo $temp

Let me know if there is an efficient way to do this!

drl · #3 06-14-2008

Hi.

I think you should be pleased that you created a solution. There are many ways to approach problems in *nix. For long files, while-read loops can be very time-consuming. You can often use utilities to process an entire file. Here is one example with your situation:

Code:

#!/bin/bash -

# @(#) s2       Demonstrate collapse of all lines in file to a single line.

echo
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1) tr sed
echo

FILE=${1-data1}
echo " Input file $FILE:"
cat $FILE

temp=$( tr '\n' ',' <$FILE )

echo
echo " Contents of string after tr:"
echo $temp

temp1=${temp/%,/}
echo
echo " Contents of string after clean-up:"
echo $temp1

temp2=$( echo $temp | sed 's/,$//' )
echo
echo " Contents of cleaned string, sed alternative:"
echo $temp2

exit 0

Producing:

Code:

% ./s2

(Versions displayed with local utility "version")
Linux 2.6.11-x1
GNU bash 2.05b.0
tr (coreutils) 5.2.1
GNU sed version 4.1.2

 Input file data1:
1
2
3
4
5

 Contents of string after tr:
1,2,3,4,5,

 Contents of string after clean-up:
1,2,3,4,5

 Contents of cleaned string, sed alternative:
1,2,3,4,5

The tr translates characters in an entire file. The subsequent special assignment with the variable is peculiar to some shells, so I provided a alternative sed step to remove the final ",".

See man pages for details.

For the size of problems such as this is likely to be, most solutions are probably the same in efficiency. However, it is useful to know about other methods in general ... cheers, drl

i.scientist · #4 06-14-2008

thanks for the solution. my problem is solved. your method looks efficient.

------------------------------------------------------------
echo
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1) tr sed
echo
--------------------------------------------------------------
But the above did not give any results except :
(Versions displayed with local utility "version")

Is this just printing version i am using ?

drl · #5 06-14-2008

Hi.

The command version is something that I wrote to document versions of commands that I use in scripts. I don't expect that you would have it, which is why the first part of the statement causes the remainder of the statement to be skipped. It works on my systems, but nothing is produced when version is not present in your path ... cheers, drl

fpmurphy · #6 06-15-2008

This works in ksh93

Code:

var=$(<file1)
var=${var//
/,}

print $var

and outputs

Code:

1,2,3,4,5

i.scientist · #7 06-15-2008

It works.

Thank you all for your answers.

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