/bin/sleep is Linux or Unix command to delay for a specified amount of time. You can suspend the calling shell script for a specified time. For example, pause for 10 seconds or stop execution for 2 mintues. In other words, the sleep command pauses the execution on the next shell command for a given time.
How do I delay a script in Linux?
Within the script you can add the following in between the actions you would like the pause. This will pause the routine for 5 seconds. read -p “Pause Time 5 seconds” -t 5 read -p “Continuing in 5 Seconds….” -t 5 echo “Continuing ….”
What is $? In Linux shell script?
$? is a special variable in shell that reads the exit status of the last command executed. After a function returns, $? gives the exit status of the last command executed in the function.
How do you end a shell script in Linux?
To end a shell script and set its exit status, use the exit command. Give exit the exit status that your script should have. If it has no explicit status, it will exit with the status of the last command run.
What is PS EF command in Linux?
This command is used to find the PID (Process ID, Unique number of the process) of the process. Each process will have the unique number which is called as PID of the process.
How do I run a shell script?
Steps to write and execute a script
- Open the terminal. Go to the directory where you want to create your script.
- Create a file with . sh extension.
- Write the script in the file using an editor.
- Make the script executable with command chmod +x <fileName>.
- Run the script using ./<fileName>.
How do I wait in bash script?
wait is typically used in shell scripts that spawn child processes that execute in parallel. To illustrate how the command works, create the following script: #!/bin/bash sleep 30 & process_id=$! echo “PID: $process_id” wait $process_id echo “Exit status: $?”
How do I run a bash script?
Make a Bash Script Executable
- 1) Create a new text file with a . sh extension. …
- 2) Add #!/bin/bash to the top of it. This is necessary for the “make it executable” part.
- 3) Add lines that you’d normally type at the command line. …
- 4) At the command line, run chmod u+x YourScriptFileName.sh. …
- 5) Run it whenever you need!
What is $1 script Linux?
$1 is the first command-line argument passed to the shell script. … $0 is the name of the script itself (script.sh) $1 is the first argument (filename1) $2 is the second argument (dir1)
What is $? In Unix?
The $? variable represents the exit status of the previous command. Exit status is a numerical value returned by every command upon its completion. … For example, some commands differentiate between kinds of errors and will return various exit values depending on the specific type of failure.
Which Linux shell is best?
Top 5 Open-Source Shells for Linux
- Bash (Bourne-Again Shell) The full form of the word “Bash” is “Bourne-Again Shell,” and it is one of the best open-source shells available for Linux. …
- Zsh (Z-Shell) …
- Ksh (Korn Shell) …
- Tcsh (Tenex C Shell) …
- Fish (Friendly Interactive Shell)