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I've got several files in a folder, with the following names:

FILE_201.txt
FILE_206.txt
FILE_215.txt
FILE_223.txt
FILE_229.txt
FILE_232.txt

I want to select files between two values (e.g. between "210" and "230"). From the command line, running

ls -1 FILE_{210..230}.txt

lists the desired files; no problem. However, if I run the following Bash script, 

#!/bin/bash
ls -1 FILE_{$1..$2}.txt

passing 210 and 230 as arguments to it, it doesn't work.

What am I doing wrong?

jub0bs
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urgeo
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2 Answers2

2

The problem isn't about running the command at the command line or from a script. You can check that for yourself, by running the following at the command line:

$ set 210 230 # assigns variables $1 and $2 the values "210" and "230", resp.
$ ls -1 FILE_{$1..$2}.txt
ls: FILE_{210..230}.txt: No such file or directory

As you can see, you get the same error as the one raised by your script file. The problem is that brace expansion happens before variable expansion.

In this case, by the time, $1 and $2 get expanded to 210 and 230, it's too late for the range to be interpreted as such; the { .. } part simply sticks around, without any special meaning attached to it.

Anyway, using ls here is a bad idea, because you're going to get an error for each filename in the range that doesn't match an existing file. You'd be better off using a combination of a for loop and seq, as in this answer:

#!/bin/bash

# test.sh

for n in $(seq $1 $2); do 
    f="FILE_$n.txt"
    if [ -e $f ]; then
        printf $s\\n "$f"
    fi
done

Example:

$ touch FILE_209.txt
$ touch FILE_213.txt
$ touch FILE_224.txt
$ touch FILE_232.txt
$ bash test.sh 210 230
FILE_213.txt
FILE_224.txt
Community
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jub0bs
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    Your answer in http://stackoverflow.com/q/29007821/1983854 was perfectly good, only that the other one helped me better. Please consider undeleting it, since it adds value to the whole question! – fedorqui Mar 12 '15 at 13:09
  • @fedorqui Thanks, but I realised one problem with it: if, for some reason, you want to check out all the files from a commit *other than the current one*, `git reset --hard ` will reset your current branch to ``, whereas poke's `git checkout -- .` will not. – jub0bs Mar 12 '15 at 13:12
0

In case anyone is interested, you need to "eval" your line. i.e.

eval "ls FILE_{$1..$2}.txt
Lungang Fang
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