-e file file merely exists (may be protected from user) -r file file exists and is readable by user -w file file is writable by user -x file file is executable by user -o file file is owned by user -z file file has size 0 -f file file is an ordinary file -d file file is ...
#if-else # run cmd as if expression if ({grep -s junk $1}) then echo "We found junk in file $1" endif # check if the var is defined if ($?dirname) then ls $dirname endif if (-e somefile) then grep $1 somefile else echo "Grievous error! Database file does not exist". ...
此方法将路径作为输入并测试用户的权限。...让我们看下面的示例,该示例使用fs.access()检查给定目录是否存在: const fs = require('fs'); // directory to check if exists const...'does not exist' : 'exists'}`); }); 查看本指南,以了解有关在Node.js应用程序中读写文件的更多信息。 12.2K10 如何...
-e file file merely exists (may be protected from user) -r file file exists and is readable by user -w file file is writable by user -x file file is executable by user -o file file is owned by user -z file file has size 0 -f file file is an ordinary file -d file file is ...
Csh的使用 Csh的使⽤ 在*unix系统中，常⽤的shell有sh，bash，csh/tcsh, ksh.sh来⾃于systemV的Unix，是传统的Unix的shell，直到现在很多的系统管理员仍然喜欢使⽤sh。bash来⾃于BSD Unix，语法⾮常类似于C语⾔，所以通常有C/C++编程背景的开发⼈员最喜欢使⽤。ksh是对sh的扩展，且吸收了csh...
-r filename Return true, or 1 if the user has read access. Otherwise it returns false, or 0. -w filename True if the user has write access. -x filename True if the user has execute permission (or search permission on a directory). -e filename True if filename exists. -o...
–efilename True if filename exists. –ofilename True if the user owns filename. –z filename True if filename is of zero length (empty). –ffilename True if filename is a plain file. –dfilename True if filename is a directory.If...
if ev.exists(env) and not args.dir: if ev.exists(env) and not args.dir: @@ -141,17 +134,10 @@ def env_deactivate_setup_parser(subparser): def env_deactivate(args): def env_deactivate(args): if not args.shell: if not args.shell: msg = ...
>& filename >&! filename Uses filename as the standard output. If the file does not exist then it is created; if the file exists, it is truncated; its previous contents are lost. If the variable noclobber is set, then the file must not exist or be a character special file (fo...
When you invoke thecshcommand, it begins by looking in your home directory and executing commands from the.cshrcfile (used to store customized user information) if it exists. If thecshcommand runs as a login shell, it executes commands from your.cshrcand.loginfiles. ...