[bash] Read file's content into variable problem

Coolmax · 08-21-2009, 07:16 PM

Hi, I'm trying to read content of file to variable and use this variable in for loop. The problem is, when I have c++ comment style in file - /*. Spaces in line are also interpreted as separated lines. For example:

Code:

mateusz2@susek:~> cat file.txt
first_line
second_line
third_line
/*
some
text
*/
problem line
again_ok

mateusz2@susek:~> cat script.sh
#!/bin/sh
files="`cat $1`"

for x in $files
do
	echo "$x"
done

mateusz2@susek:~> ./script.sh file.txt
first_line
second_line
third_line
/bin
/boot
/dev
/etc
/home
/lib
/lost+found
/media
/mnt
/opt
/proc
/root
/sbin
/srv
/sys
/tmp
/usr
/var
some
text
dw/
scripts/
problem
line
again_ok

Changing $files to "$files" eliminate these problems but causes that whole content of variable is treated as one string (one execution of loop).

druuna · 08-21-2009, 07:26 PM

This should work, if you are willing to change your script:

Code:

#!/bin/sh

cat $1 | while read THISLINE
do
  echo "${THISLINE}"
done

The double quotes around ${THISLINE} are needed.

catkin · 08-22-2009, 04:38 AM

Your script is

Code:

#!/bin/sh
files="`cat $1`"

for x in $files
do
	echo "$x"
done

Is "files" really "lines"?

druuna · 08-22-2009, 06:20 AM

@catkin: What are you trying to say?
files is just a name of a variable, why would it matter if it is files, lines or anything else?

Please elaborate if I misunderstand your remark/question.

Coolmax · 08-22-2009, 06:47 AM

Thanks druuna, but loading file to "files" variable I have in "case of" statement (after getopt), so I change:

Code:

cat $1 | while read x

to:

Code:

echo "$files" | while read x

and this work too

Thanks again. Best regards.

catkin · 08-22-2009, 09:58 AM

Hello Druuna

Quote:

Originally Posted by druuna

@catkin: What are you trying to say?
files is just a name of a variable, why would it matter if it is files, lines or anything else?

Please elaborate if I misunderstand your remark/question.

I was quoting from Coolmax's OP, not your suggestion.

You are 100% correct, of course, any variable names will work but choice of variable names typically reflects the programmer's intentions.

Sometimes understanding what the LQ questioner wants to do is half the task of answering. In this case Coolmax's description and code suggested different things; the variable $files was used to hold lines of a single file. I wanted to clarify the contradiction before answering.

Best

Charles

Coolmax · 08-31-2009, 05:12 PM

Quote:

Originally Posted by catkin

Hello Druuna

I was quoting from Coolmax's OP, not your suggestion.

You are 100% correct, of course, any variable names will work but choice of variable names typically reflects the programmer's intentions.

Sometimes understanding what the LQ questioner wants to do is half the task of answering. In this case Coolmax's description and code suggested different things; the variable $files was used to hold lines of a single file. I wanted to clarify the contradiction before answering.

Best

Charles

@catkin, I called this variable $files, because lines are URLs to files. Script is simply downloader.