echo"the variable X is not the empty string" fi 运行这个脚本,输出如下: the variable X is not the empty string 为何?这是因为shell将$X展开为空字符串,表达式[-n]返回真值(因为改表达式没有提供参数)。再看这个脚本: 1 2 3 4 5 #!/bin/bash X="" if[ -n"$X"];then# -n 用来检查变量是...
An crray is like a series of slots that hold values. Each slot is known as an element, and each element can be accessed via a numerical index. An array element can contain a string or a number, and you can use it just like any other variable. The indices for arrays start at 0 and...
#.bash_profile # Get the aliases and functionsif[-f~/.bashrc ]; then <==底下这三行在判断并读取 ~/.bashrc.~/.bashrc fi # User specific environment and startup programsPATH=$PATH:$HOME/.local/bin:$HOME/bin<==底下这几行在处理个人化设定exportPATH 这个文件内有设定 PATH 这个变量喔!而且还...
echo 'Please enter your name.' #Here we are reading the standard input and assigning it to the variable name with the read command. read name #We are now going back to standard output, by using echo and printing your name to the command line. echo "With standard input you have told m...
ShellCheck is built and packaged using Cabal. Install the packagecabal-installfrom your system's package manager (with e.g.apt-get,brew,emerge,yum, orzypper). On macOS (OS X), you can do a fast install of Cabal using brew, which takes a couple of minutes instead of more than 30 minu...
variable assignments, etc. */REDIRECT*redirects;/* Redirections to perform. */}SIMPLE_COM; while命令结构: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 /* WHILE command. */typedef struct while_com{int flags;/* See description of CMD flags. */COMMAND*test;/* Thing to test. */COMMAND...
lock/lock file log/log file and directory opt/variable date for opt run/date relevnat to runing processes spool/application spool date tmp/temporary files /procKernel and processes information virtual filesystem,基于内存的虚拟文件系统,存储内核和进程的相关信息,多为内核参数 ...
name=jerry,name:2结果为rryname:2结果为rry{variable:pos:num}: 偏移pos个字符,取num个字符长度的子串 name=‘hello world’, ${name:2:5}结果为“llo w” 字符串处理,将来在bash中经常用的 bash能力分为三个最为重要: 字符串能力 grep,awk,sed ...
#!/bin/bash #write a variable NAME=“William” #use that variable echo“Hello $NAME” 用户还可以通过用户输入来填充变量: #!/bin/bash echo“Hello $1, that is a $2 name” 在终端中: ~$bash name.sh “William” “great” Hello William, that is a great name 还可以使用 read 之类的命令...
到目前为止,以下是我所拥有的,其中DYNAMIC_VARIABLE_NAME_HERE将是我们可以从${file##*/}中获得的名称: #!/bin/bash # check and load config files required_files=( './config/foo' './config/bar' ) for file in "${required_files[@]}"; do ...