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--- start [2008/04/22 14:00] – Bash Shell Script Variablen IF Komperation Bourne gerald
+++ start [Unbekanntes Datum] (aktuell) – gelöscht - Externe Bearbeitung (Unbekanntes Datum) 127.0.0.1
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-A quick guide to writing scripts using the bash shell:
-http://pegasus.rutgers.edu/~elflord/unix/bash-tute.html
-Command Substitution:
-http://www.injunea.demon.co.uk/pages/page206.htm
-The Linux Terminal - a Beginners' Bash:
-http://linux.org.mt/article/terminal
-bash shell script:
-wichtug, dass am Anfang:
-#!/bin/bash
-Das ist wichtig, weil der User, sollte er eine andere Shell als Bash gew�lt haben, eine ander Syntax vorherrschen kann.
-Variablen:
-x="hallo" # wichtig: KEINE Leerzeichen bei dem '='
-$1, $2 etc. 1., 2., etc Parameter beim Aufruf
-Um Variablen zu unterscheiden (z.B. /hallo/wer$binich/denn ist falsch, weil Interpreter nicht
-weiss, wo Variable endet). Richtig: /hallo/wer${bin}ich/denn
-Quoting:
-bei echo '$x' kommt raus: $x
-bei echo "$x" kommt raus: hallo
-" interpretiert Variablen,
-' tut das nicht! (sondern 'w�tlich')
-parameter /variables substitution:
-http://www.unet.univie.ac.at/aix/aixuser/usrosdev/parameter_subst.htm#AC8A8CF676shar
-#!/bin/bash
-X=""
-if [ -n "$X" ]; then    # -n tests to see if the argument is non empty
-        echo "the variable X is not the empty string"
-else
-	echo "empty!"
-fi
-http://pegasus.rutgers.edu/~elflord/unix/bash-tute.html:
-A brief summary of test operators
- Here's a quick list of test operators. It's by no means comprehensive, but its likely to be all you'll need to remember (if you need anything else, you can always check the bash manpage ... )
-operator
-produces true if...
-number of operands
--n
-operand non zero length
--z
-operand has zero length
--d
-there exists a directory whose name is operand
--f
-there exists a file whose name is operand
--eq
-the operands are integers and they are equal
--neq
-the opposite of -eq
-=
-the operands are equal (as strings)
-!=
-opposite of =
--lt
-operand1 is strictly less than operand2 (both operands should be integers)
--gt
-operand1 is strictly greater than operand2 (both operands should be integers)
--ge
-operand1 is greater than or equal to operand2 (both operands should be integers)
--le
-operand1 is less than or equal to operand2 (both operands should be integers)
-Expressions may be unary or binary. Unary expressions are often used to examine the status of a file. There are string operators and numeric comparison operators as well. If the file argument to one of the primaries is of the form `/dev/fd/N', then file descriptor N is checked. If the file argument to one of the primaries is one of `/dev/stdin', `/dev/stdout', or `/dev/stderr', file descriptor 0, 1, or 2, respectively, is checked.
--a file
-True if file exists.
--b file
-True if file exists and is a block special file.
--c file
-True if file exists and is a character special file.
--d file
-True if file exists and is a directory.
--e file
-True if file exists.
--f file
-True if file exists and is a regular file.
--g file
-True if file exists and its set-group-id bit is set.
--h file
-True if file exists and is a symbolic link.
--k file
-True if file exists and its "sticky" bit is set.
--p file
-True if file exists and is a named pipe (FIFO).
--r file
-True if file exists and is readable.
--s file
-True if file exists and has a size greater than zero.
--t fd
-True if file descriptor fd is open and refers to a terminal.
--u file
-True if file exists and its set-user-id bit is set.
--w file
-True if file exists and is writable.
--x file
-True if file exists and is executable.
--O file
-True if file exists and is owned by the effective user id.
--G file
-True if file exists and is owned by the effective group id.
--L file
-True if file exists and is a symbolic link.
--S file
-True if file exists and is a socket.
--N file
-True if file exists and has been modified since it was last read.
-file1 -nt file2
-True if file1 is newer (according to modification date) than file2.
-file1 -ot file2
-True if file1 is older than file2.
-file1 -ef file2
-True if file1 and file2 have the same device and inode numbers.
--o optname
-True if shell option optname is enabled. The list of options appears in the description of the `-o' option to the set builtin (see section 4.3 The Set Builtin).
--z string
-True if the length of string is zero.
--n string
-string
-True if the length of string is non-zero.
-string1 == string2
-True if the strings are equal. `=' may be used in place of `=='.
-string1 != string2
-True if the strings are not equal.
-string1 < string2
-True if string1 sorts before string2 lexicographically in the current locale.
-string1 > string2
-True if string1 sorts after string2 lexicographically in the current locale.
-arg1 OP arg2
-OP is one of `-eq', `-ne', `-lt', `-le', `-gt', or `-ge'. These arithmetic binary operators return true if arg1 is equal to, not equal to, less than, less than or equal to, greater than, or greater than or equal to arg2, respectively. Arg1 and arg2 may be positive or negative integers.
-nette einfhrung:
-http://www.tu-berlin.de/zrz/information/paper/instant/sh/sh-03.html
-Werte eines Files in Veriablen einlesen
-Achtung: Dieses Skript liest wortweise ein (Leerzeichen getrennt) und ignoriert Leerzeichen/Leerzeilen
-#!/bin/sh
-ISOPATH=/data1/iso
-DESTINATION=/mnt/iso
-ls ${ISOPATH} > /tmp/isomount.tmp
-index=1
-ISO=""
-for x in `cat /tmp/isomount.tmp`
-do
- ISO[index]="$x"
- index=`expr $index +1`
-done
-for y in `echo ${ISO[@]}`
-do
- mkdir -p ${DESTINATION}/y
- mount -o loop -t iso9660 ${ISOPATH}/y ${DESTINATION}/y
-done
-exit 0
-Datei zeile fr zeile lesen: script <datei
-> while [ true ]
-> do
->         read X  #read a line
->         if [ $? -ne 0 ] #Break if EOF
->         then
->                 break
->         fi
->         echo $X #Your action goes here.
-> done < tmp.txt
-gut:
-http://steve-parker.org/sh/bourne.html

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