Shell Scripting unwanted '?' character at the end of file name

bash shell cp
premprakash picture premprakash · Nov 6, 2012 · Viewed 13.5k times · Source

I get an unwanted '?' at the end of my file name while doing this: 

emplid=$(grep -a "Student ID" "$i".txt  | sed 's/(Student ID:  //g' | sed 's/)Tj//g' ) 
 #gets emplid by doing a grep from some text file
echo "$emplid"   #prints employee id correctly 
cp "$i" "$emplid".pdf  #getting an extra '?' character after emplid and before .pdf

i.e instead of getting the file name like 123456.pdf , I get 123456?.pdf . Why is this happening if the echo prints correctly? How can I remove trailing question mark characters ?

Answer

Gordon Davisson picture Gordon Davisson · Nov 6, 2012

It sounds like your script file has DOS-style line endings (\r\n) instead of unix-style (just \n) -- when a script in this format, the \r gets treated as part of the commands. In this instance, it's getting included in $emplid and therefore in the filename.

Many platforms support the dos2unix command to convert the file to unix-style line endings. And once it's converted, stick to text editors that support unix-style text files.

EDIT: I had assumed the problem line endings were in the shell script, but it looks like they're in the input file ("$i".txt) instead. You can use dos2unix on the input file to clean it and/or add a cleaning step to the sed command in your script. BTW, you can have a single instance of sed apply several edits with the -e option:

emplid=$(grep -a "Student ID" "$i".txt  | sed '-e s/(Student ID:  //g' -e 's/)Tj//g' -e $'s/\r$//' )

I'd recommend against using sed 's/.$//' -- if the file is in unix format, that'll cut off the last character of the filename.

Related questions

Linux: copy and create destination dir if it does not exist

I want a command (or probably an option to cp) that creates the destination directory if it does not exist. Example: cp -? file /path/to/copy/file/to/is/very/deep/there

Read More
How to force 'cp' to overwrite directory instead of creating another one inside?

I'm trying to write a Bash script that will overwrite an existing directory. I have a directory foo/ and I am trying to overwrite bar/ with it. But when I do this: cp -Rf foo/ bar/ a new bar/foo/ …

Read More
Recursive copy of specific files in Unix/Linux?

I need to copy all *.jar files from directory and all its subdirectories. How can I do it in UNIX/Linux terminal? Command cp -r *.jar /destination_dir doesn't work.

Read More