Porteus

Code: Select all

#!/bin/bash 
 
if [ "$1" == "" ]; then
  echo "== works - $ 1 = null"
fi
if [ -z $1 ]; then
  echo "-z works - $ 1's length = 0"
fi
if [ -n $1 ]; then
  echo "-n works - $ 1's length > 0"
fi

Code: Select all

guest@porteus:~$ ./test.sh x
-n works - $ 1's length > 0

guest@porteus:~$ ./test.sh 
== works - $ 1 = null
-z works - $ 1's length = 0
-n works - $ 1's length > 0
guest@porteus:~$ 

Code: Select all

Except for -h and  -L,  all  FILE-related  tests  dereference  symbolic
       links.   Beware  that  parentheses  need  to be escaped (e.g., by back‐
       slashes) for shells.  INTEGER may also be -l STRING, which evaluates to
       the length of STRING.

Code: Select all

#!/bin/bash 
if [ "$1" = "" ]; then
  echo "= works - $ 1 = null"
fi
if [ -z "$1" ]; then
  echo "-z works - $ 1's length = 0"
fi
if [ -n "$1" ]; then
  echo "-n works - $ 1's length > 0"
fi

root@riposo:~/works# ./testIT x
-n works - $ 1's length > 0
root@riposo:~/works# ./testIT
= works - $ 1 = null
-z works - $ 1's length = 0
root@riposo:~/works# 

Code: Select all

guest@porteus:/tmp$ ./test.sh
== works - $ 1 = null
-z works - $ 1's length = 0
-n works - $ 1's length > 0

guest@porteus:/tmp$ ./test.sh x
-n works - $ 1's length > 0

guest@porteus:/tmp$ bash -x ./test.sh
+ '[' '' == '' ']'
+ echo '== works - $ 1 = null'
== works - $ 1 = null
+ '[' -z ']'
+ echo '-z works - $ 1'\''s length = 0'
-z works - $ 1's length = 0
+ '[' -n ']'
+ echo '-n works - $ 1'\''s length > 0'
-n works - $ 1's length > 0

guest@porteus:/tmp$ ./test.sh  << set -x used
+ '[' '' == '' ']'
+ echo '== works - $ 1 = null'
== works - $ 1 = null
+ '[' -z ']'
+ echo '-z works - $ 1'\''s length = 0'
-z works - $ 1's length = 0
+ '[' -n ']'
+ echo '-n works - $ 1'\''s length > 0'
-n works - $ 1's length > 0
guest@porteus:/tmp$