Shell中的expr命令
阿新 • • 發佈：2018-12-17
expr EXPRESSION
將EXPRESSION的值列印到標準輸出
- 使用index命令
test="AaBbCcDdEeFfGg"
echo $(expr index $test A)
echo $(expr index $test D)
echo $(expr index $test Z)
- 使用substr命令
echo $(expr substr $test 2 5)
- 使用match命令
#test not start with a, return 0 echo $(expr match $test "a*") #test start with A, return 1 echo $(expr match $test "A*") #test end with g, return matched position 14 echo $(expr match $test ".*g$") #test not end with G, return 0 echo $(expr match $test ".*G$") echo $(expr match $test "\(.*g$\)") echo $(expr match $test "\(A*\)")
程式碼段
/bin/bash test="AaBbCcDdEeFfGg" echo $(expr index $test A) echo $(expr index $test D) echo $(expr index $test Z) echo $(expr substr $test 2 5) #test not start with a, return 0 echo $(expr match $test "a*") #test start with A, return 1 echo $(expr match $test "A*") #test end with g, return matched position 14 echo $(expr match $test ".*g$") #test not end with G, return 0 echo $(expr match $test ".*G$") echo $(expr match $test "\(.*g$\)") echo $(expr match $test "\(A*\)") echo $(expr length $test) echo $(expr 5 = 5) echo "bye..."
執行結果
