就像if 使用fi 来结束一样,在条件列完之后必须用">"来结束。 7.1.1.2. 后接then语句的命令 CONSEQUENT-COMMANDS 列出了跟在 then 语句后面可以是任何有效的UNIX命令,任何可执行的程序,任何可执行的shell脚本或者任何shell语句,除了 fi. 。重要地记住 then 和 fi 在shell里面被认为是分开的语句。因此,在命令行上...
Also be aware that you can have multipleelifstatements but only oneelsestatement in an if construct and it must be closed with afi. Using nested if statements in bash You can also use an if statement within another if statement. For example, take a look at the followingweather.shbash scrip...
CONSEQUENT-COMMANDS列出了跟在then语句后面可以是任何有效的UNIX命令,任何可执行的程序,任何可执行的shell脚本或者任何shell语句,除了fi. 。重要地记住then和fi在shell里面被认为是分开的语句。因此,在命令行上使用的时候,他们用分号隔开。 在脚本中,if语句的不同部分通常是良好分隔的。以下是一些简单的例子: 7.1.1.3...
Basic If statements A basic if statement commands that if a particular condition is true, then only execute a given set of actions. If it is not true, then do not execute those actions. If statement is based on the following format: Syntax of If statement if condition then Code block exe...
$?" # 上一个命令的退出状态 echo "current shell process ID: \$$ $$" # 执行当前 bash 脚本的进程ID sleep 10 & # & 符号的主要作用是将命令放入新的子进程执行, 主脚本会立即执行后续命令 echo "process ID of recent backend commands: \$! $!" # 返回最近一个后台命令的进程 ID sleep 1 ...
if 语句的语法是: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ifCOMMANDSthen<COMMANDS>elif<COMMANDS># optional then<COMMANDS>else<COMMANDS># optional fi # required 再次强调,[是一个命令,它同其它常规的命令一样接受参数。if 是一个复合命令,它包含其它命令,[并不是 if 语法中的一部分。
NOTE:You can tie multiple commands using bash operators to achieve the best result. For example, you can allow sleep to execute only if ping and echo execute successfully. $ ping -c 1 linuxhint.com && echo "Success" || sleep 100; ...
When an interactive shell that is not a login shell is started, bash reads and executes commands from ~/.bashrc, if that file exists. This may be inhibited by using the –norc option. The –rcfile file option will force bash to read and execute commands from file instead of ~/.bashrc...
for name in ${dirlist[@]} do # if: if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]... [ else COMMANDS; ] fi # 如果是文件, if [ -f $1/$name ]; then #并且$2不存在该文件,则直接copy if [ ! -f $2/$name ]; then...
Some Bash commands can only be run by the root user; a system administrator or superuser. If you try one of these commands without sufficient privileges, it fails. For example, only users logged in as a superuser can usecatto display the contents of/etc/at.deny: ...