What is if Z $1 in shell script?

What is if Z $1 in shell script?

[ “$1” = “” ] and [ -z “$1” ] are exactly equivalent in bash and other POSIX-compliant shells. (Note that there must be a space on each side of the brackets, unless there is a non-word-constituent character like ; .)

What is Z command in Linux?

-z STRING means the length of STRING is zero .

What does [- Z $1 mean in bash?

$1 means an input argument and -z means non-defined or empty. You’re testing whether an input argument to the script was defined when running the script. Follow this answer to receive notifications.

What does Z means in bash?

Use the -z Flag in Bash The test command can be used with a parameter. The -z flag is a parameter that checks if the length of a variable is zero and returns true if it is zero. In the example below, the -z flag is used with the test command, and it is tested whether the given string is empty. Bash.

What does if [- Z in bash?

Code: if [ -z $SOMEVARIABLE ]; then echo “Do something here …. ” In both cases, the -z flag is a parameter to the bash’s “test” built-in (a built-in is a command that is built-into the shell, it is not an external command). The -z flag causes test to check whether a string is empty.

What is S in bash?

From man bash : -s If the -s option is present, or if no arguments remain after option processing, then commands are read from the standard input. This option allows the positional parameters to be set when invoking an interactive shell.

What does if [- F mean shell?

From bash manual: -f file – True if file exists and is a regular file. So yes, -f means file ( ./$NAME. tar in your case) exists and is a regular file (not a device file or a directory for example). Follow this answer to receive notifications.

What is directory Z?

To z, a directory that has low ranking but has been accessed recently will quickly have higher rank than a directory accessed frequently a long time ago.

What does the keystroke command Z do?

Command-Z: Undo the previous command. You can then press Shift-Command-Z to Redo, reversing the undo command. In some apps, you can undo and redo multiple commands.

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