Remove the first and last char in the file

Question

I have a data file, and I want to remove the first and last char. Is there a simple way to do this? I searched online, but I didn't find a simple way. Thanks!

Answer 1

Try:

sed -i '1s/.\(.*\)/\1/; $s/\(.*\)./\1/' path/to/file.txt

-i : modify file in place

1s : apply substitute command to line number 1 only

$s : apply substitute command to last line only

\\( ... \\) : a capture group to make use of later by referencing it with \\1

Basically these are two sed substitute commands glued with ;

EDIT: Just realized you said simple... Not sure if this falls under simple.

Answer 2

Could you please try following, if you are ok with awk .

awk '
prev{
  if(++count==1){
      print substr(prev,2)
  }
  else{
      print prev
  }
  prev=""
}
{
  prev=$0
}
END{
  if(prev){
      print substr(prev,1,length(prev)-1)
  }
}'    Input_file

Answer 3

Using awk*. Testing with Lorem\\nipsum (no trailing newline, as otherwise that would be removed**):

$ echo -en Lorem\\nipsum | awk -v RS="^$" '{gsub(/^.|.$/,"")}1'
orem
ipsu

Solution reads the whole input into memory before processing so that could be considered a downside.

* Succesfully tested with gawk, awk-20121220 and Busybox awk, failed with mawk.

** "Last character":

$ echo -e Lorem\\nipsum  # outputs:
Lorem\n
ipsum\n                  # \n is last char but print (well, 1) adds another

To avoid that, use printf instead:

$ echo -e Lorem\\nipsum | awk -v RS="^$" '{gsub(/^.|.$/,"");printf "%s",$0}'
orem
ipsum$