shell 字符串

发布时间：2020-12-15 23:14:22 所属栏目：安全来源：网络整理

导读：-z“字符串”? ?：若字符串长度为0 则为真? ? -z? zero 【-z "$myvar"】 ? [[email?protected] ~]# [ ! -z "liwm" ] echo 1 ||echo 0 1 ? ? -n“字符串”? ?若字符串长度不为0则为真? -n? ?no zero? 【-n "$myvar"】 [[email?protected] ~]# [ -n "liwm" ] e

-z“字符串”? ?：若字符串长度为0 则为真? ? -z? zero

【-z "$myvar"】

[[email?protected] ~]# [ ! -z "liwm" ]&& echo 1 ||echo 0
1

-n“字符串”? ?若字符串长度不为0则为真? -n? ?no zero?

【-n "$myvar"】

[[email?protected] ~]# [ -n "liwm" ]&& echo 1 ||echo 0
1

[[email?protected] ~]# [ -n "" ]&& echo 1 ||echo 0
0

等号两边需要空格

[[email?protected] ~]# sed -n ‘30,31p‘ /etc/init.d/network
# Check that networking is up.
[ "${NETWORKING}" = "no" ] && exit 6

[[email?protected] ~]# vim /etc/init.d/nfs

# Source networking configuration.
[ -f /etc/sysconfig/network ] && . /etc/sysconfig/network

# Check for and source configuration file otherwise set defaults
[ -f /etc/sysconfig/nfs ] && . /etc/sysconfig/nfs

# Remote quota server[ -z "$RQUOTAD" ] && RQUOTAD=`type -path rpc.rquotad`

（编辑：李大同）

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