echo "$a = $b: a != b" fi if [ -n $a ] then echo "-n $a : The string length is not 0" else echo "-n $a : The string length is 0" fi if [ $a ] then echo "$a : The string is not empty" else echo "$a : The string is empty" fi 结果 abc = efg: a != ...
Break and Continue for Loop Break Statement Continue Statement Examples of Bash for Loops Share Loops are one of the most powerful and fundamental programming concepts that allow users to execute a command or set of commands repeatedly. The Loops come in very handy for all programmers where they...
Example-3: Reading Command-line arguments Command-line arguments values can be iterated by using for loop in bash. Create a new bash file named loop3.sh with the following script to read and print the command-line argument values using for loop. #!/bin/bash # Define loop to read argument...
There is three loop constructs available in bash: for-loop, while-loop, and until-loop. All the bash loop constructs have a return status equals to the exit status of the last command executed in the loop, or zero if no command was executed. The For loop...
commandN done 1. 2. 3. 4. 5. 6. OR for OUTPUT in $(Linux-Or-Unix-Command-Here) do command1 on $OUTPUT command2 on $OUTPUT commandN done 1. 2. 3. 4. 5. 6. Examples This type of for loop is characterized by counting. The range is specified by a beginning (#1) and ending...
·loop:挂载文件。 后面两个参数指定了该存储设备的设备文件位置以及挂载点在虚拟目录中的位置。 例如,手动将U盘/dev/sdb1挂载到/media/disk,可以使用下列命令: mount -t vfat /dev/sdb1 /media/disk 一旦存储设备被挂载到虚拟目录,root用户就拥有了对该设备的所有访问权限,而其他用户的访问则会被限制。可以通过...
loop:挂载一个文件 -o + loop命令完成将一个iso文件直接挂载到Linux虚拟目录中,而不先将它烧到CD里 umount命令 从Linux上移除一个可移动的设备时不能直接从系统上移除,应先卸载 umount:支持通过设备文件和设备挂载点来指定要卸载的设备,如果有任何程序正在使用设备上的文件,系统不会允许你卸载 ...
command1 command2 commandn done Let us now check a few example usages of the bash for loop. Bash For Loop Example In its simplest form, thefor looptakes the following basic format. In this example, the variableniterates over a group of numerical values enclosed in curly braces and prints...
On the execution of this updated code with the Bash command, we have got the inner loop executed 9 times i.e., 3 times for each iteration of the outer loop. The output is presented in the affixed image. $bashbash.sh Example 03: Nested For Loop in One line ...
echo "123" > a.out for d in $(ls -d subdir*); do cd $d; pwd; cp ../a.out .; cd ..;done 我反复使用身体 for d in $(ls $PATTERN); do $COMMAND ;done 在更广泛的背景下,有一些$COMMAND。加速的一个选项是bash函数。 function loop () { ...