即, 无论$dir$name存在与否,file$dir$name的状态返回值都将是0, 即表示成功 所以不能使用file命令来判断文件是否存在. manfile 返回值项如下: RETURN CODE file returns 0 on success, and non-zero on error. If the file named by the file operand does not exist, cannot be read, or the type of...
About “bash if file does not exist” issue You might want to check if file does not exist in bash in order to make the file manipulation process easier and more streamlined. This is the job of the test command, which can check if a file exists and its type. Since only the check is...
#!/usr/bin/env bash # File: whileloop.sh count=3 while [[ $count -gt 0 ]] do echo "count is equal to $count" let count=$count-1 done WHILE循环首先以while关键字开头,然后是一个条件表达式。只要循环迭代开始时条件表达式等价于true,那么WHILE循环中的代码将继续执行。当我们运行这个...
[student@studentvm1 testdir]$ File="TestFile1" ; echo "This is file $File" > $File ; if [ -s $File ] ; then echo "$File exists and contains data." ; else echo "$File does not exist or is empty." ; fi TestFile1 exists and contains data. 现在加入elif语句来辨别是文件不存在...
Bash 提供三种循环语法for、while和until。 1、while 循环 cat tmp |while read hostname file;do echo $hostname :; ssh root@$hostname "ls -l $file" </dev/null;done while循环有一个判断条件,只要符合条件,就不断循环执行指定的语...
x=5; if [ $x = 5 ]; then echo 'x equals 5.'; else echo 'x does not equal...
Why does the error "bash warning setlocale LC_CTYPE cannot change locale (en_US.UTF-8) No such file or directory" error occurs while switching to root? Solution Verified- UpdatedAugust 5 2024 at 5:11 AM- English Issue Unable to login in system or switch torootuser. Below error message ...
4.2、while循环 格式: while condition do command done 特殊用法:遍历文件的每一行 while read VAR_NAME; do command(s) done < /path/to/somefile 4.3、until循环 until 的用法跟 while 的类似,只是在 until 后面的语句为假的时候执行循环体。
"$BASH_ENV"; fi but the value of the PATH variable is not used to search for the file name. If bash is invoked with the name sh, it tries to mimic the startup behavior of historical versions of sh as closely as possible, while conforming to the POSIX standard as well. When invoked...
Default Global Packages From File While InstallingIf you have a list of default packages you want installed every time you install a new version, we support that too -- just add the package names, one per line, to the file $NVM_DIR/default-packages. You can add anything npm would accept...