| Advanced Bash-Scripting Guide: An in-depth exploration of the art of shell scripting | ||
|---|---|---|
| Prev | Chapter 35. Bash, versions 2 and 3 | Next |
On July 27, 2004, Chet Ramey released version 3 of Bash. This update fixes quite a number of bug in Bash and adds some new features.
Some of the added features are:
A new, more generalized {a..z} brace expansion operator.
1 #!/bin/bash
2
3 for i in {1..10}
4 # Simpler and more straightforward than
5 #+ for i in $(seq 10)
6 do
7 echo -n "$i "
8 done
9
10 echo
11
12 # 1 2 3 4 5 6 7 8 9 10 |
The ${!array[@]} operator, which expands to all the indices of a given array.
1 #!/bin/bash
2
3 Array=(element-zero element-one element-two element-three)
4
5 echo ${Array[0]} # element-zero
6 # First element of array.
7
8 echo ${!Array[@]} # 0 1 2 3
9 # All the indices of Array.
10
11 for i in ${!Array[@]}
12 do
13 echo ${Array[i]} # element-zero
14 # element-one
15 # element-two
16 # element-three
17 #
18 # All the elements in Array.
19 done |
The =~ Regular Expression matching operator within a double brackets test expression. (Perl has a similar operator.)
1 #!/bin/bash 2 3 variable="This is a fine mess." 4 5 echo "$variable" 6 7 if [[ "$variable" =~ "T*fin*es*" ]] 8 # Regex matching with =~ operator within [[ double brackets ]]. 9 then 10 echo "match found" 11 # match found 12 fi |