This is the basic Schell Scripting tutorial with an example
File existence checks:
- -f file True if the file exists and is an ordinary file.
- -d file True if the file exists and is a directory.
- -s file True if the file exists and is not empty.
- -c file True if the file exists and is a character device file.
- -b file True if the file exists and is a block devise file.
File access checks:
- -r file True if the file exists and has read permission to it.
- -w file True if the file exists and has a write permission to it.
- -x file True if the file exists and has a execute permission to it
String Check Operation:
- [ -n string ] True if the string is not zero.
- [ -z string ] True if the string is zero.
- [ string ] True if the string is not empty.
Special symbols with additional info:
- $# Total number of positional parameters.
- $@ Represents all the parameters i.e. $1 to the end.
- $? Pass or fail status of the last command executed.
- $$ Process id of the currently running shell.
- $! Process id of the last run background process.