given a plain text document with several lines like:
c48 7.587 7.39 c49 7.508 7.345983 c50 5.8 7.543 c51 8.37454546 7.34 I need to add some info 2 spaces after the end of the line, so for each line I would get:
c48 7.587 7.39 def c49 7.508 7.345983 def c50 5.8 7.543 def c51 8.37454546 7.34 def I need to do this for thousands of files. I guess this is possible to do with sed, but do not know how to. Any hint? Could you also give me some link with a tutorial or table for this cases?
Thanks
if all your files are in one directory
sed -i.bak 's/$/ def/' *.txt to do it recursive (GNU find)
find /path -type f -iname '*.txt' -exec sed -i.bak 's/$/ def/' "{}" +; you can see here for introduction to sed
Other ways you can use,
awk
for file in * do awk '{print $0" def"}' $file >temp mv temp "$file" done Bash shell
for file in * do while read -r line do echo "$line def" done < $file >temp mv temp $file done 
+;? I always use \;. The bash manpage doesn't make me any wiser.
find's man page. its equivalent to xargs
NR, eg awk 'NR==3{..}' file means do for line 3
for file in ${thousands_of_files} ; do sed -i ".bak" -e "s/$/ def/" file done The key here is the search-and-replace s/// command. Here we replace the end of the line $ with 2 spaces and your string.
Find the sed documentation at http://sed.sourceforge.net/#docs
sed is a Unix utility so it uses the Unix convention, i.e. ending each line with Carriage Return - CR (^M), while macs uses Line Feed - LF (^L), Windows BTW uses CR,LF. Thepoint is that you are left with the Unix EOL character. I am not a Mac guru, but there should be a utility to fix this. On my Linux box there is dos2unix and unix2dos, but if you can't find such a tool, try using tr '\r' '\f' to get a similar effect.