Shell Variables are empty when called in a file name but not when echo'd or called elsewhere

Question

I have 4 shell variables set

remote_account="raccname"
remote_machine="server"
First_Name="firstname"
Last_Name="lastname"

when I call remote_account or remote_machine in my script they get used fine

echo "What directory shall you choose?"
  read dir
  scp -r ~/csc60/$dir $remote_account@$remote_machine:directoryA
  exit;;

but when I call the other two as such

echo "What directory shall you choose?"
  read dir
  scp $remote_account@$remote_machine:tars/$Last_Name_$First_Name_$dir.tar.z ~/tars
  exit;;

it grabs the tars file from tars/$dir.tar.z completely skipping $Last_Name_$First_Name_ when I throw an echo $Last_Name in it still shows it as "lastname"

Is there some rule using "_" between variables or something, or am I just missing something obvious?

Hint, check out question http://stackoverflow.com/questions/951336/how-to-debug-a-bash-script — hyde, Sep 29 '13 at 06:56

score 5 · Accepted Answer · answered Sep 29 '13 at 06:53

5

_ is a valid character for variable names, therefore you have to qualify which part is the variable.

scp "$remote_account@$remote_machine:tars/${Last_Name}_${First_Name}_$dir.tar.z" ~/tars

answered Sep 29 '13 at 06:53

Ignacio Vazquez-Abrams

776,304
153
1,341
1,358

Ah Thanks so much mate I knew it was something simple – Justin D Sep 29 '13 at 06:58

Alpesh Gediya · Answer 2 · 2013-09-29T07:02:51.043

0

You need to delimit your variable value using ${}, as you declared $Last_Name_$First_Name_$dir is treated as one variable and shell put value for it. As in your case you did not defined value for it . It will be intepreted as "".

use ${LAST_NAME}_${FIRST_NAME}

edited Sep 29 '13 at 07:02

answered Sep 29 '13 at 06:56

Alpesh Gediya

3,706
1
25
38

Thanks for the in depth answer, much appreciated – Justin D Sep 29 '13 at 07:12

Shell Variables are empty when called in a file name but not when echo'd or called elsewhere

2 Answers2