how to join lines

glamo_2312 · #1 (**permalink**) 09-11-2008

can anyone tell me as "how to join all lines in a file " using a shell script
Actually i have many files in a directory and for each file i want to join all the lines using a shell scrip .

Thanks in advance!!!

jim mcnamara · #2 (**permalink**) 09-11-2008

This joins a list of files into one line per file in a new file

Code:


while read file
do
      tr -d '\n' < $file
      echo ""
done < list_of_files > newfile

Niroj · #3 (**permalink**) 09-11-2008

echo " Enter the dir name: [Give full path] "
read dir
cd $dir

for file in `ls`
do
if [ -f $file ]; then # Plz try to check & avoid *.gz , *.out & *.4ge
# and other binary files
echo `cat $file`> $file
fi
done

era · #4 (**permalink**) 09-11-2008

That's a Useless Use of ls in Backticks there. You mean

Code:

for file in *

That's also a Useless Use of Cat; or rather, it will replace runs of newlines with a single space, which is kind of borderline; certainly the lines are joines, but spaces are also added. If that's not desired, try

Code:

tr -d '\n' <"$file" >tmp;  mv tmp "$file"

(If your tr doesn't understand \n, try with \012 or a literal newline between the single quotes. It looks weird but it's perfectly valid syntax.)

If you want to replace each newline with a space, that's also easy to do with tr.

Niroj · #5 (**permalink**) 09-11-2008

ok...Herder of Useless Cats..
cool... I knew the result thats why I suggested this...
Ex.
cat > File
=============
hi era
bye
=========
tr -d '\n' <"File" >tmp; mv tmp "File"
=====
cat file
----------------
hi erabye # Any one need this type of joining.. ??!

================================================
And 2nd one ...
If you think "translating each '\n' char to NULL value; then creating a temp file and then renaming the temp file to acutual file name to make it permanent .. " is faster and better idea..
Then I don't need to say anything...!!

era · #6 (**permalink**) 09-12-2008

Depends on the requirements, obviously. If you want spaces then (as hinted) try

Code:

tr '\n' ' ' <File >tmp

Temporary files are obviously a wart, but if this is part of a complex process, the command is probably part of a longer pipeline anyway, and so no temporary file will be needed. If you want a one-liner without a temporary file, try Perl.

Code:

perl -i~ -pe 'y/\n//d' file  # or 'y/\n/ /' if you want to join with spaces

Niroj · #7 (**permalink**) 09-12-2008

Quote:

Originally Posted by era

Depends on the requirements, obviously. If you want spaces then (as hinted) try

Code:

tr '\n' ' ' <File >tmp

Temporary files are obviously a wart, but if this is part of a complex process, the command is probably part of a longer pipeline anyway, and so no temporary file will be needed. If you want a one-liner without a temporary file, try Perl.

Code:

perl -i~ -pe 'y/\n//d' file  # or 'y/\n/ /' if you want to join with spaces

=======================
What a greate idea..as if anyone know these...?!!
Plese don't make thse silly comments..

Then tell me why using cat is useless...

echo `cat $file`> $file ?

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