In case you want to check if more than one file exists, you can still do so. Similar to the above situations, use “-f” and test if a file you’re trying to locate is still there. Separate the files by using the “&&” operator. For example, you want to test if 1 file 1 an...
Let’s take a look at the code that is used to check if the directory of the folder exists in our system or not. For that, we will be using a purely new folder. Therefore, within the terminal shell query area, we have tried the “mkdir” command to create a new directory named “...
We will check if the directory exists and if not, then we will create a new one. if (dir.exists("my_new_folder")) { print("The direcoty exists") } else { # create the "my_new_folder dir.create("my_new_folder") } And the folder “my_new_folder” created under our ...
# input check: if [ -z "$1" ] ; then error "ERROR: you must specify a file, use -h for help" fi filen="$1" # rename any .1 , .2 etc file: for n in 9 8 7 6 5 4 3 2 1; do if [ -f "$filen.$n" ]; then p=`expr $n + 1` echo "mv $filen.$n $filen...
if ...; then ... elif ...; then ... else ... fi 大多数情况下,可以使用测试命令来对条件进行测试。比如可以比较字符串、判断文件是否存在及是否可读等等… 通常用" [ ] "来表示条件测试。注意这里的空格很重要。要确保方括号的空格。 [ -f ...
check if folder not exist if [ ! -d "$PROJECTNAME" ] then printf "\n Repo $PROJECTNAME folder does not exist..\n" else printf "\n Repo $PROJECTNAME folder already exist..\n" fi Array Create array # method 1 declare -a FontColor=() #method 2 FontColor[0]='yellow' FontColor[...
if [ -r "$rpmpackage" ];then echo "=== $rpmpackage ===" rpm -qi -p $rpmpackage else echo "ERROR: cannot read file $rpmpackage" fi done 这里出现了第二个特殊的变量$*,该变量包含了所有输入的命令行参 数值。如果您运行showrpm openssh.rpm...
-z foo - Check if variable exists String Operators = - Equals == - Equals -z - Is null -n - Is not null < - Is less than in ASCII alphabetical order > - Is greater than in ASCII alphabetical order If Statements #!/bin/bash if [[$foo = 'bar']]; then echo 'one' elif [[...
if [ -f "$newfile" ]; then echo "ERROR: $newfile exists already" else echo "renaming $file to $newfile ..." mv "$file" "$newfile" fi fi done 这是一个复杂一些的例子。让我们详细讨论一下。第一个if表达式判断输入命令行参数是否小于3个 (特殊变量$# 表示包含参数的个数) 。如果输入参...
Create a Random File or Folder The following script is used to print the current username,system uptime informationalong with the current date and time, and appends this data to a text file. Finally, the script shows the user of the directory where the file is being saved using thepwd comm...