-z STRING True if string is empty. -n STRING STRING True if string is not empty. 即,test命令使用-z STRING操作符来判断STRING字符串的长度是否为 0。 如果为 0,就是空字符串,会返回 true。 具体写法是test -z STRING,使用[命令则写为[ -z STRING ]。 -n STRING操作符判断STRING字符串的长度是否...
echo "$a : The string is not empty" else echo "$a : The string is empty" fi 结果 abc = efg: a != b -n abc : The string length is not 0 abc : The string is not empty 文件测试运算符 实例: #!/bin/bash file="/home/shiyanlou/test.sh" if [ -r $file ] then echo "The ...
Let’s look at another option, “-z”, used so far in Bash to check for the empty string. The code has been started with Bash support, and we have initialized a string variable “v” with the value “Hello” in it. Then, we started the “if-else” statement to check whether the ...
empty_string="" if[ $X -lt $Y ]# is $X less than $Y ? then echo"$X=${X}, which is smaller than $Y=${Y}" fi if[ -n"$empty_string"];then echo"empty string is non_empty" fi if[ -e"${HOME}/.fvwmrc"];then# test to see if ~/.fvwmrc exists echo"you have a .fv...
if [ -n "$empty_string" ]; then echo "empty string is non_empty" fi if [ -e "${HOME}/.fvwmrc" ]; then # test to see if ~/.fvwmrc exists echo "you have a .fvwmrc file" if [ -L "${HOME}/.fvwmrc" ]; then # is it a symlink ?
版权声明:本文为博主原创文章,转载请注明源地址。...https://blog.csdn.net/10km/article/details/50427281 linux shell中判断目录是否为空 #!.../bin/sh ##方法一 判断输出字符数统计为0 is_empty_dir(){ ...
How To Bash Shell Find Out If a Variable Is Empty Or Not #!/bin/bashJAIL="/nginx"HINT=""# Do three possibilities for $JAIL ##for i in 1 2 3 docase $i in1) JAIL="/nginx/jail"; HINT="value set";;2) JAIL=""; HINT="value set to empty string";;3) unset JAIL; HINT="...
# return the last character of a string in $rval if [ -z "$1" ]; then # empty string rval="" return fi # wc puts some space behind the output this is why we need sed: numofchar=`echo -n "$1" | wc -c | sed 's/ //g' ` ...
is readable-s FILE_NAM # TrueifFILE_NAM existsandisnotempty-w FILE_NAM # TrueifFILE_NAM has write permission-x FILE_NAM # TrueifFILE_NAM is executable#字符串测试操作-z STRING # TrueifSTRING is empty-n STRING # TrueifSTRING isnotemptySTRING1...
# return the last character of a string in $rval if [ -z "$1" ]; then # empty string rval="" return fi # wc puts some space behind the output this is why we need sed: numofchar=`echo -n "$1" | wc -c | sed 's/ //g' ` ...