Variable with '-' (minus signals) in Bash

Question

This is so simple yet...

FOLDER='/home/user/.ssh'
SSH="$FOLDER/local-rsync-key.pub"
if [ -f "$SSH" ]; then
...

It looks that Bash considers the '-' as a minus signal and the IF statement always fails... How can I write this variable the right way?

UPDATE: This is another real example:

I am tring to rename files with "-" in front of the filename, for example: "-0001.jpg"

However, everyime I try to run:

for i in *; do mv "$i" "${i//-/}"; done

or:

for i in *; do mv "$i" "${i#*-}"; done

I got this error:

mv: invalid option -- '0'
Try `mv --help' for more information.

Thanks for any light!

It seems to be a duplicate of [this](http://stackoverflow.com/questions/6557985/mv-invalid-option-0) quetion. — Lynch, Jul 02 '11 at 16:59

paxdiablo · Answer 1 · 2011-06-23T22:27:37.937

You should not have a $ in front of your SSH assignment, that's only needed when you're using the variable. Without that, it works fine, as in the following transcript:

pax> touch abc-xyz

pax> ll a*
-rw-r--r-- 1 pax paxgrp 0 2011-06-24 05:15 abc-xyz

pax> FOLDER=.

pax> $SSH="$FOLDER/abc-xyz"
bash: =./abc-xyz: No such file or directory

pax> SSH="$FOLDER/abc-xyz"

pax> if [ -f "$SSH" ]
...> then
...>     echo yes
...> fi
yes

pax> _

score 3 · Accepted Answer · answered Jul 02 '11 at 17:01

3

The answer is to use "--" (indicating no more options) after "mv" or "./" before the name of the file (indicating it is about a file). For example:

for i in *; do mv -- "$i" "${i#*-}"; done

or:

for i in *; do mv -- "$i" "./${i#*-}"; done

answered Jul 02 '11 at 17:01

Roger

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It's worth noting that this works for pretty much any Linux tool ever. `find` is one notable exception. – l0b0 Jul 05 '11 at 14:27

score 1 · Answer 3 · answered Jun 23 '11 at 21:17

In bash syntax, when you set a variable just use the variable name:

VAR=value

When you reference the variable, use the $ prefix:

echo $VAR

Your code has a stray dollar sign prefix where you are trying to set the SSH variable. The dashes inside the variable should be no problem.

Variable with '-' (minus signals) in Bash

3 Answers3