如果用户的输入项少于read命令给出的变量数目,那么额外的变量值为空。如果用户的输入项多于定义的变量,那么多余的输入项会包含到最后一个变量中。如果read命令之后没有定义变量名,那么环境变量REPLY会包含所有的输入。#!/bin/bash # read-single: read multiple values into default variable echo -n "Enter one ...
array+=("$line")the line variable stores the value of each line in the file and using this argument, it gets stored in an array. done < "$file"instructs the loop to read the filename from the$fileusing the input redirection<. ...
There are several methods to read user input into a variable in Bash, here are some commonly used methods to do it: using the read command using a prompt 1: Using the read Command The read command is used to receive user input from the command line and store it in a variable, the sy...
脚本入门 read 命令 条件判断 循环 函数 数组 set 命令 脚本除错 mktemp 命令,trap 命令 启动环境 命令提示符 Shell 的含义 学习Bash,首先需要理解 Shell 是什么。Shell 这个单词的原意是“外壳”,跟 kernel(内核)相对应,比喻内核外面的一层,即用户跟内核交互的对话界面。
Create a bash file and then add the below-mentioned code in this file to read the file content. You can store the previous text file into a new variable$filenameand variable$nis used to keep the value of each line. Now, using the while loop we will read each line from a file with...
IFS 內部欄位分隔符 Internal Field Separator 用來在擴充套件之後進行分詞,使用內部命令 read 將行劃分成 詞。預設值是 ``<space><tab><newline>''。 IGNOREEOF 控制互動式 shell 接受到唯一一個 EOF 字元時的行為。如果有定義,值是需要在一行的開始連續輸入 EOF 字元,直到可以使 bash 退出的字元個數。
REPLY 变量的值将作为内建命令 read 的输入,如果命令没有参数的话。 SECONDS 每次引用这个参数时,返回 shell 自运行以来的秒数。如果向 SECONDS 赋值,此后对它的引用将返回自赋值时 起的秒数加上所赋予的值。如果取消 SECONDS 的定义,它就失去了特殊的意义,即使后来重新定义它。 SHELLOPTS 一个冒号分隔的被允许...
while read LREAD do echo ${LREAD} done < /etc/passwd | head -n 5 Input Redirection You can also store the file name to a variable and pass it through a redirection operator. FILENAME="/etc/passwd" while read LREAD do echo ${LREAD} ...
When bash is started non-interactively, to run a shell script, for example, it looks for the variable BASH_ENV in the environment, expands its value if it appears there, and uses the expanded value as the name of a file to read and execute. Bash behaves as if the following command ...
When executing interactively, bash displays the primary prompt PS1 when it is ready to read a command, and the secondary prompt PS2 when it needs more input to complete a command. Bash allows these prompt strings to be customized by inserting a number of backslash-escaped special characters that...