From AdminWiki

Revision as of 01:04, 24 May 2006 (view source) Gullevek (Talk | contribs) ← Older edit		Revision as of 01:05, 24 May 2006 (view source) Gullevek (Talk | contribs) (→Questions and Solutions) Newer edit →
Line 15:		Line 15:
	== Questions and Solutions ==		== Questions and Solutions ==
		+
		+	Below some examples for bash problems that might come up
	=== Arrays in Bash: ===		=== Arrays in Bash: ===

---

Revision as of 01:05, 24 May 2006

Contents 1 Bash 1.1 Error and Output Redirect 1.2 Questions and Solutions 1.2.1 Arrays in Bash: 1.2.2 Variable Variables 1.2.3 Variable Variables in Arrays 1.3 More Documentation

Bash

Bash is the most common shell form on linux, and most other unix systems.

Just a small reminder. Before you start writing a long bash script, think if you can do this in perl.

Error and Output Redirect

to redirect output and error

 ls -l 1>normal_out 2>error_out

if you want to have both in one file

 ls -l 1>normal_out 2>&1

Questions and Solutions

Below some examples for bash problems that might come up

Arrays in Bash:

 foo[0]=1;
 foo[1]=2;
 foo[2]=3;
 # loop
 for (( i=0; i<${#foo[@]}; i++ ));
 do
     echo ${foo[$i]};
 done;
 # more like a foreach
 for i in ${foo[@]};
 do
     echo $i;
 done;

Variable Variables

 foobar=5;
 bar="foobar";
 echo $foobar;
 echo $bar;
 echo ${!bar};

Variable Variables in Arrays

 foo[0]=1;
 foo[1]=2;
 foo[2]=3;
 foo_tcp[0]="AT";
 foo_upd[0]="AU";
 foo_tcp[1]="BT";
 foo_upd[1]="BU";
 foo_tcp[2]="CT";
 foo_upd[2]="CU";
 # loop
 for (( i=0; i<${#foo[@]}; i++ ));
 do
     echo ${foo[$i]};
     for k in upd tcp;
     do
         data=foo_${k}[$i];
         echo ${!data};
     done;
 done;

More Documentation

The best advanced guide for bash scripting: http://www.tldp.org/LDP/abs/html/