# Interpolation issues in a backticks expression
**URL:** https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612
**Category:** General Usage
**Created:** [March 9, 2018, 5:25pm UTC](https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612 "2018-03-09T17:25:53Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jonathanBieler](https://discourse.julialang.org/u/jonathanBieler)
#### Post date: [March 9, 2018, 5:25pm UTC](https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612/1 "2018-03-09T17:25:53Z")
I’m trying to build this command:
```
osascript -e 'tell application "Terminal" to do script "julia -i $path/file.jl"'
```
Where `$path` is a julia variable, But I can’t manage to get it to work, any idea ?
Thanks.
---
### Author:  [@Simon\_Bolland](https://discourse.julialang.org/u/Simon_Bolland)
#### Post date: [March 10, 2018, 11:23am UTC](https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612/2 "2018-03-10T11:23:05Z")
Seems to be single quotes that are preventing variable expansion in command.
Escaping them expands $path in command
```julia
path="/tmp/path"
cmd=`osascript -e \'tell application "Terminal" to do script "julia -i $path/file.jl"\'`
julia> dump(cmd)
Cmd
exec: Array{String}((9,))
1: String "osascript"
2: String "-e"
3: String "'tell"
4: String "application"
5: String "Terminal"
6: String "to"
7: String "do"
8: String "script"
9: String "julia -i /tmp/path/file.jl'"
ignorestatus: Bool false
flags: UInt32 0
env: Void nothing
dir: String ""
```
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [March 10, 2018, 1:05pm UTC](https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612/3 "2018-03-10T13:05:10Z")
> [@jonathanBieler](#):
>
> osascript -e 'tell application “Terminal” to do script “julia -i $path/file.jl”
The problem here is that you have to know how escaping rules work for `osascript`. For example, what if the `path` contains a space, a quote, a dollar sign, or some other special character? Assuming it uses standard shell-like escaping, you can maybe do (I don’t really know `osascript`) something like:
```julia
p = sprint(escape_string, joinpath(path, "file.jl"), "\$!")
s = "tell application \"Terminal\" to do script \"julia -i \\\"$p\\\"\""
`osascript -e $s`
```
Note that you want to pass the argument to `-e` as a single string. No additional quotes are needed around the string, because the `osascript` command is not being executed in the shell.
Avoiding this kind of escaping issue is precisely the reason that backtick-commands in Julia avoid the shell, so you are re-opening that can of worms by passing through _two_ layers of shell: one in the `osascript` command that you are trying to construct, and another in the shell command executed by the `osascript` command. (I may be missing another level of backslashes in the nested shell command above! You’ll need to test things out.)
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [March 10, 2018, 1:22pm UTC](https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612/4 "2018-03-10T13:22:57Z")
I just tried the code I suggested, and an extra level of backslashes is required for filenames containing `$`:
```julia
using Compat
sescape(s) = replace(sprint(escape_string, s, "\$!"), "\\"=>"\\\\")
p = sescape(joinpath(path, "file.jl"))
s = "tell application \"Terminal\" to do script \"julia -i \\\"$p\\\"\""
run(`osascript -e $s`)
```
Again, all these backslashes are essentially because you are going through three levels of escaping: Julia literal string escaping, osascript’s string escaping, and the shell escaping.
(Even this might not be enough escaping for file names containing `"` characters, I haven’t tried that.)
---
### Author:  [@jonathanBieler](https://discourse.julialang.org/u/jonathanBieler)
#### Post date: [March 10, 2018, 4:02pm UTC](https://discourse.julialang.org/t/interpolation-issues-in-a-backticks-expression/9612/5 "2018-03-10T16:02:37Z")
That works yes, thanks!