Use the which command to check if the specified bash command exists.Use which Command 1 2 3 4 5 6 7 if which wget > /dev/null; then echo "wget command exists." else echo "wget command does not exist." fioutput
if!type"$foobar_command_name"> /dev/null;then# install foobar here,or poping up some warning messagesfi references: http://stackoverflow.com/questions/7522712/how-to-check-if-command-exists-in-a-shell-script http://stackoverflow.com/questions/592620/how-to-check-if-a-program-exists-from-a...
Check if a File or Directory Exists Using Code Snippets The previous commands work well for a simple two-line command at a command prompt. However, you can also useBashwith multiple commands. When several commands are strung together, they are called ascript. Ascriptis usually saved as a fil...
When you type this command on Bash, the output should look something like this $ /etc. exists on your file system. Using short terms Similar to how you can use short terms to test if a file exists on Bash, you can also do the same for the directory. In the bash shell, you can u...
Catkin tools installed successfully."fi}create_catkin_ws(){# Checkifworkspace existsif[ -e"$CATKIN_DIR/.catkin_workspace"] || [ -d"$CATKIN_DIR/.catkin_tools"]; thenecho"Catkin workspace detected at ~/catkin_ws"elseecho"Creating catkin workspace ...
if[ -e"${HOME}/.fvwmrc"];then# test to see if ~/.fvwmrc exists echo"you have a .fvwmrc file" if[ -L"${HOME}/.fvwmrc"];then# is it a symlink ? echo"it's a symbolic link elif[ -f"${HOME}/.fvwmrc"];then# is it a regular file ?
When writing Shell scripts, you may find yourself in a situation where you need to perform an action based on whether a file exists or not. In Bash, you can use the test command to check whether a file exists and determine the type of the file....
Here is a example of while loop controlled by standard input. Until the redirection chain from STDOUT to STDIN to the read command exists the while loop continues. #!/bin/bash# This bash script will locate and replace spaces # in the filenames ...
continue # read next file and skip the cp command fi # we are here means no backup file exists, just use cp command to copy file /bin/cp $f $f.bakdone 放在一起 Bash for循环对于自动化IT中的重复任务非常有用。让我们看看如何在多个Linux或Unix服务器上运行一个简单的命令(例如正常运行时间)...
So, if you cannot find a command and it cannot even be installed, you should try searching on the internet if that command even exists. If it does not, probably it was an alias on some other system. Method 4: Check if it is an executable script with correct path ...