1、判斷資料夾是否存在
if [ -d /home/q/www ];then echo "
true
"; else echo "
false
";fi
(系統內存在資料夾 /home/q/www)
2、判斷檔案是否存在
if [ -e /etc/passwd ];then echo "
true
"; else echo "
false
";fi
if [ -f /etc/passwd ];then echo "
true
"; else echo "
false
";fi
檔案存在且大小大於0
if [ -s /etc/passwd ];then echo "
true
"; else echo "
false
";fi
3、判斷檔案可讀
if [ -r /etc/passwd ];then echo "
true
"; else echo "
false
";fi
4、判斷檔案可寫
if [ -w /etc/passwd ];then echo "
true
"; else echo "
false
";fi
5、判斷檔案可執行
if [ -x /etc/passwd ];then echo "
true
"; else echo "
false
";fi
6、字串長度為0,返回真
長度為0
if [ -z "" ];then echo "
true
"; else echo "
false
";fi
長度不為0
if [ -z "
xiaoqiang
" ];then echo "
true
"; else echo "
false
";fi
7、字串長度不為0,返回真
長度不為0
if [ -n "
xiaoqiang
" ];then echo "
true
"; else echo "
false
";fi
長度為0
if [ -n "" ];then echo "
true
"; else echo "
false
";fi
8、判斷字串相等
if [ "
xiaoqiang
" = "
xiaoqiang
" ];then echo "
true
"; else echo "
false
";fi
9、判斷字串不相等
if [ "
xiaoqiang
" != "
xiaoqiang
" ];then echo "
true
"; else echo "
false
";fi
10、判斷整數相等
if [ 1 -eq 1 ];then echo "
true
"; else echo "
false
";fi
11、判斷整數不相等
if [ 1 -ne 1 ];then echo "
true
"; else echo "
false
";fi
12、判斷整數 1
< 2
if [ 1 -lt 2 ];then echo "
true
"; else echo "
false
";fi
13、判斷整數 2
<= 2
if [ 2 -le 2 ];then echo "
true
"; else echo "
false
";fi
14、判斷整數3 > 2
if [ 3 -gt 2 ];then echo "
true
"; else echo "
false
";fi
15、判斷整數 3 >= 3
if [ 3 -ge 3 ];then echo "
true
"; else echo "
false
";fi
16、邏輯運算
!(非)
if [ ! 3 -ge 3 ];then echo "
true
"; else echo "
false
";fi
-a(and)
if [ -z "" -a 3 -ge 3 ];then echo "
true
"; else echo "
false
";fi
-o(或)
if [ -z "
sadfsa
" -o 3 -ge 3 ];then echo "
true
"; else echo "
false
";fi
17、特殊變數
echo
"number:$#
"獲取引數個數
echo
"scname:$0
"獲取指令碼名稱
echo
"first:$1
"獲取第乙個引數
echo
"second:$2
"獲取第二個引數
echo
"argume:$@
"獲取所有引數
echo
"show parm list :$*
"資料引數的list
echo
"show process id :$$
"獲取程序id
echo
"show precomm stat:$?
" 獲取命令執行的結果
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