=’. When it is used, the string to the right of the operator is considered a POSIX extended regular expression and matched accordingly (using the POSIX regcomp and regexec interfaces usually described in regex(3)). The return value is 0 if the string matches the pattern, and...
/bin/bash# Shebang line: Indicates the path to the shell interpreter (in this case, bash)# Prompt the user to enter a numberecho"Input a number:"readn# Check if the number is greater than 100if["$n"-gt100];thenecho"The number is greater than 100."elseecho"The number is not greate...
Bash's exit status is the exit status of the last command executed in the script. If no commands are executed, the exit status is 0. An attempt is first made to open the file in the current directory, and, if no file is found, then the shell searches the directories in PATH for ...
if type -p executable_name &>/dev/null; then # Program is in PATH. fi # 反向检测. if ! type -p executable_name &>/dev/null; then # Program is not in PATH. fi # 示例(如果未安装程序,则提前退出). if ! type -p convert &>/dev/null; then printf '%s\n' "error: convert is ...
You can also get the path to the executable to where it was installed:nvm which 12.22In place of a version pointer like "14.7" or "16.3" or "12.22.1", you can use the following special default aliases with nvm install, nvm use, nvm run, nvm exec, nvm which, etc:...
Check if a Directory Exists in Bash To check if adirectoryexists, switch the-foption on thetestcommand with-d(for directory). For example: test -d /tmp/test echo $? The output is1, which means that the directory doesn't exist. Create the directory using themkdir commandand rerun the ...
Check if file does not exists if [ ! -f /tmp/users.txt ]; then echo "File not found" fi Parameterize file name in script to check if file doesn’t exist filecheck.sh #!/bin/bash FILEPATH=$1 if [ ! -f "$FILEPATH" ]; then ...
Method 4: Check if it is an executable script with correct path This is a common mistake Linux rookies make whilerunning a shell script. Even if you are in the same directory and try to run an executable script just by its name, it will show an error. ...
To check if a file is locked or not, type: lsattr /etc/exim.conf The "i" in this case refers to the word "immutable", meaning to be unchangeable over time. You'd see the 'i' in the list of other flags (usually just many --- characters) if a file is locked. #...
–Check if file is nonzero size -u filename –Check if file set-user-id bit is set -w filename –Check if file is writable -x filename –Check if file is executable Related Simplifying File Existence Checking in R with file.exists() Introduction As a programmer, you’ll oft...