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Updated SC2070 (markdown)

koalaman
2015-12-05 17:26:57 -08:00
parent e6299f1668
commit c2ad75fc62
1 changed files with 6 additions and 6 deletions
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12
SC2070.md

@@ -1,4 +1,4 @@
## Always true because you failed to quote. Use [[ ]] instead.
## -n doesn't work with unquoted arguments. Quote or use [[ ]].
### Problematic code:
@@ -13,10 +13,10 @@ fi
### Correct code:
In bash/ksh:
In POSIX:
```sh
if [[ -n $var ]]
if [ -n "$var" ]
then
echo "var has a value"
else
@@ -24,10 +24,10 @@ else
fi
```
In POSIX:
In bash/ksh:
```sh
if [ -n "$var" ]
if [[ -n $var ]]
then
echo "var has a value"
else
@@ -47,7 +47,7 @@ When `$var` is unquoted, a blank value will cause it to wordsplit and disappear.
`[ string ]` is shorthand for testing if a string is empty. This is still true if `string` happens to be `-n`. `[ -n ]` is therefore true, and by extension so is `[ -n $var ]`.
To fix this, either use `[[ -n $var ]]` which has fewer caveats than `[`, or quote the variable.
To fix this, either quote the variable, or (if your shell supports it) use `[[ -n $var ]]` which generally has fewer caveats than `[`.
### Exceptions: