`who` command will execute first that print the user’s information of the currently logged in user. The output of the `who` command will execute by `echo` command and the output of `echo` will store into the variable$var. Here, the output of `echo` command depends on the output...
Variable=$(command) You can also add additional text to support the command output as shown here: Variable="Optional text $(command)" Let me give you a simple example. Here, I have used the whoami command to find the currently logged-in user withthe echo command: echo "The current user...
查阅 网页原文内容 on Command root# curl www.sina.com 保存/下载 指定URL的网页 on FileSystem/Disk 如果要把这个网页保存下来,可以使用-o参数(output),这就相当于使用wget命令了。 不带文件路径值时,默认下载到当前窗口所在的本地路径。 root# curl -o [Dir/文件名] www.sina.com 若想显示下载进度条,...
Occasionally you might want to run a command like you would on the command line and store the result of that command in a variable. We can do this by wrapping the command in a dollar sign and parentheses ($( )) around a command. This syntax is calledcommand substitution. The command is...
operate-and-get-next ( C-o ) 提交并执行当前行,然后从历史中取出相对于当前行的下一行进行编辑。忽略任何参数。 edit-and-execute-command ( C-x C-e ) 启动一个编辑器来编辑当前行,并把结果当作 shell 命令来执行。Bash会试图依次启动 $VISUAL,$EDITOR 和 emacs 作为编辑器。
possible-command-completions (C-x !) 列出point 之前的文本可能的補全,將它視爲命令名。 dynamic-complete-history (M-TAB) 嘗試對 point 之前的文本進行補全,將此文本與歷史列表中的行相比較來查找可能的補全匹配。 complete-into-braces (M-{) 進行文件名補全,將可能的補全列表放在花括號中插入,使得列表可以...
Output of script: VARIABLE-TRACE> $variable = “”VARIABLE-TRACE> $variable = “29”Just initialized $variable to 29.VARIABLE-TRACE> $variable = “29”VARIABLE-TRACE> $variable = “87”Just multiplied $variable by 3.VARIABLE-TRACE> $variable = “87”Of course, the trap command has other...
bash: PI: readonly variable As you can see, you can only read the value of a constant variable, but you can never change its value after it is created. Command substitutions The ability to store the output of a command into a variable is called command substitution and it’s by far on...
variables using another flag which is “-n”. The following command of export is set with the flag “-n” to unset these environment variables. The output displayed that the “export -p” command is undone with the command “export -n”, the variable is limited to the running shell ...
which was the return value ofbadcommand. But theechocommand itself succeeds, and therefore the new, most recent status is success (i.e., a0value).Because you only get one chance to check the exit status, many shell scripts will immediately assign the status to another shell variable, as ...