D
Size: a a a
OS
️
OS
Vs
is_mountp() { df --output=target -- "$1" | grep -q -- "$1"; }
--
?F
--
?F
$ echo "-1" | grep -1
Usage: grep [OPTION]... PATTERNS [FILE]...
Try 'grep --help' for more information.
$ echo "-1" | grep -- -1
-1
Vs
#!/bin/sh
dir34=/sbin
if [ -d "$dir34" ] && $(df -l -- "$dir34" | grep -qE -- " $dir34$"); then
echo disk $dir34 found!
else
echo disk not found!
fi
Лс
Лс
$ echo "1" | test -z - && echo "yes"
$ echo "" | test -z - && echo "yes"
$ test -z - && echo "yes"
Лс
Лс
$ test -z - || echo "yes"
yes
$
OM
#!/bin/sh
dir34=/sbin
if [ -d "$dir34" ] && $(df -l -- "$dir34" | grep -qE -- " $dir34$"); then
echo disk $dir34 found!
else
echo disk not found!
fi
Лс
$ echo "1" | [ -z - ] && echo "yes" || echo "no"
no
$ echo "" | [ -z - ] && echo "yes" || echo "no"
no