]; then # -n tests to see if the argument is non empty
echo "the variable X is not the emp... duces true if...
number of operands
-n
operand non zero length
1
-z
operand has zero length
1
-d
t... e. There are string operators and numeric comparison operators as well. If the file argument to one of... 2
True if file1 is newer (according to modification date) than file2.
file1 -ot file2
True if file
ere Prozesse. In letzterem Fall spricht man auch von »Pipelining«.
Zunächst fassen wir alle Möglichkeiten zur Umleitung von Ein- und Ausgaben zusammen:
<code>< datei
Standar... eitung =====
Das Programm liest nun nicht mehr von der Tastatur (stdin), sondern aus einer Datei, bi... umleitung erfolgt durch das Zeichen "<", gefolgt von einem Dateinamen.
Kommando < Dateiname
Statt
====== input passwords ======
Common practice for inputing passwords is to read the text without displaying it on the screen. The UNIX Bourne shell does not have this functionality as a command, but a combination of commands will make this work.
The stty comman... wever, it is poor programming to make the assumption that echo is on. In some cases, echoing of charac
