All files in one dir, linux
bash, linux
Solution
The behavior is correct and "as expected".
`for file in $InputDir'*'` means `assign "/home/XXX/*" to $file` (note the quotes). Since you quoted the asterisk, it will not be executed at this time. When the shell sees `echo $file`, it first expands the variables and then it does glob expansion. So after the first step, it sees
echo /home/XXX/*
and after glob expansion, it sees:
echo /home/XXX/fileA /home/XXX/fileB
Only now, it will execute the command.
In the second case, the pattern `/home/XXX/*` is expanded before the `for` is executed and thus, each file in the directory is assigned to `file` and then the body of the loop is executed.
This will work:
for file in "$InputDir"*
but it's brittle; it will fail, for example, when you forget to add a `/` to the end of the variable `$InputDir`.
for file in "$InputDir"/*
is a little bit better (Unix will ignore double slashes in a path) but it can cause trouble when `$InputDir` is not set or empty: You'll suddenly list files in the `/` (root) folder. This can happen, for example, because of a typo:
inputDir=...
for file in "$InputDir"/*
Case matters on Unix :-)
To help you understand code like this, use `set -x` ("enable tracing") in a line before the code you want to debug.
Problem
Today I tried a script in linux to get all files in one dir. It was pretty straightforward, but I found something interesting. ``` #!/bin/bash InputDir=/home/XXX/ for file in $InputDir'*' do echo $file done ``` The output is: ``` /home/XXX/fileA /home/XXX/fileB ``` But when I just input the dir directly, like: ``` #!/bin/bash InputDir=/home/XXX/ for file in /home/XXX/* do echo $file done ``` The output is: ``` /home/XXX/fileA /home/XXX/fileB ``` It seems, in the first script, there was only one loop and all the file names were stored in the variable $file in the FIRST loop, separated by space. But in the second script, one file name was stored in $file just in one loop, and there were more than one loop. What is exactly the difference between these two scripts? Thanks very much, maybe my question is a little bit naive..