Transcript UNIX - SigmaNet

Shell Programming
Guntis Barzdins
Girts Folkmanis
Lecture outline
 Shell features
 Helper utilities, introduction
 Connecting utilities with shell scripting
 Helper utilities in detail
 Piping, advanced examples
 Shell scripts as files, Internal shell commands
Shell features
 We will talk about bash, there might be differences for
other shells.



bash - GNU Bourne-Again Shell
Authors: Brian Fox and Chet Ramey
Free Software Foundation
 Popular in different distributions
 Tip: To find your current shell, type following command
$ echo $SHELL
/bin/bash
Shell Features
 The shell itself is defined in SUS (Single UNIX
Specification) as regards calling conventions and
switches. The language interpreted by the shell is
also part of the standard
 The shell standard derives from the POSIX.2
standard, which is not freely available (the current
standard, SUS, stands as IEEE Std1003.1 2001
and is identical to POSIX.2)
Shell features
 Two types of usage:


Command line - interactive
Shell script, usually non-interactive
 Shell script defined as:

"Shell Script is series of commands written in plain
text file. Shell script is just like batch file is MS-DOS
but have more power than the MS-DOS batch file."
Shell features
 Two types of commands:


Internal commands – built in the shell interpreter
External commands – calling other executable files
 Almost everything applies to both command line
usage and shell scripts
External commands
 Execution of external programs – most common
task
External program: /bin/ls
girtsf@linux tmp $ ls -l /lib
total 4035
-rwxr-xr-x
1 root root
7488
drwxr-xr-x 13 root root
1024
drwxr-xr-x
2 root root
1024
drwxr-xr-x
2 root root
2048
-rwxr-xr-x
1 root root
92716
-rwxr-xr-x
1 root root
22800
...
Oct
Oct
Jun
Aug
Oct
Oct
6
25
28
23
14
14
12:33
15:57
09:53
15:25
13:10
13:17
cpp
dev-state
evms
iptables
ld-2.3.4.so
ld-linux.so.1
External commands
 Environment variable $PATH determines where to
search for external programs.
 girtsf@linux tmp $ echo $PATH
/bin:/usr/bin:/usr/local/bin:/opt/bin
 “:” as separator
 Current directory “.” is usually not in PATH for
security reasons.
External commands
 girtsf@linux tmp $ echo $PATH
/bin:/usr/bin:/usr/local/bin:/opt/bin
 With /bin in path, typing “ls” suffices to run /bin/ls.
 Example of unsetting path:
 girtsf@linux
girtsf@linux
bash: ls: No
girtsf@linux
tmp $ unset PATH
tmp $ ls
such file or directory
tmp $
Internal commands
 A large list of built in commands, that are handled
internally without running an external command
 Most commonly used internal command is cd,
used to change the current working directory:
 girtsf@linux girtsf $ cd /tmp/
girtsf@linux tmp $
Aliasing
 Aliasing is the process of assigning a command to a
shorter “alias”
 This allows you to type the shorter command instead of the
longer one.
 Aliasing is useful for changes that you want all of the time.

alias rm “rm –i”
 Aliasing is similar to shell function definitions


dos2unix() { cat $1 | perl -pe 's/\r\n$/\n/g'; }
unix2dos() { cat $1 | perl -pe 's/\n$/\r\n/g'; }
Internal commands
girtsf@linux tmp $ help
GNU bash, version 2.05b.0(1)-release (i686-pc-linux-gnu)
These shell commands are defined internally. Type `help' to see this
list.
Type `help name' to find out more about the function `name'.
Use `info bash' to find out more about the shell in general.
Use `man -k' or `info' to find out more about commands not in this list.
A star (*) next to a name means that the command is disabled.
%[DIGITS | WORD] [&]
. filename
[ arg... ]
alias [-p] [name[=value] ... ]
bind [-lpvsPVS] [-m keymap] [-f fi
builtin [shell-builtin [arg ...]]
cd [-L|-P] [dir]
...
(( expression ))
:
[[ expression ]]
bg [job_spec]
break [n]
case WORD in [PATTERN [| PATTERN].
command [-pVv] command [arg ...]
SUS: shell grammar
%token
%token
%token
%token
%token
WORD
ASSIGNMENT_WORD
NAME
NEWLINE
IO_NUMBER
%token
/*
AND_IF
'&&'
%token DLESS
DLESSDASH
/*
'<<'
'<<-'
*/
%token
/*
OR_IF
'||'
DSEMI
';;'
*/
DGREAT
LESSAND
GREATAND
LESSGREAT
'>>'
'<&'
'>&'
'<>'
CLOBBER
'>|'
*/
/* The following are the reserved words. */
%token
/*
*/
If
'if'
%token
/*
Case
'case'
Then
'then'
Else
'else'
Esac
'esac'
Elif
'elif'
While
'while'
Fi
'fi'
Until
'until'
Do
'do'
For
'for'
Done
'done'
*/
/* These are reserved words, not operator tokens, and
are
recognized when reserved words are recognized. */
%token
/*
Lbrace
'{'
%token
/*
In
'in'
Rbrace
'}'
*/
Bang
'!'
*/
complete_command :
|
;
list
:
|
;
and_or
:
|
|
;
pipeline
:
|
;
pipe_sequence
:
|
;
command
:
|
|
|
;
compound_command :
|
|
|
|
|
|
;
subshell
:
;
compound_list
:
|
|
|
;
term
:
|
list separator
list
list separator_op and_or
and_or
pipeline
and_or AND_IF linebreak pipeline
and_or OR_IF linebreak pipeline
pipe_sequence
Bang pipe_sequence
command
pipe_sequence '|' linebreak command
simple_command
compound_command
compound_command redirect_list
function_definition
brace_group
subshell
for_clause
case_clause
if_clause
while_clause
until_clause
'(' compound_list ')'
term
newline_list term
term separator
newline_list term separator
term separator and_or
and_or
Helper utilities
 Helper utilities – various small external programs
that are helpful when working with shell scripts or
command line
 Called from shell (scripts or command line)
 Somehow transforms input into output, based on
the parameters
Helper utilities
 cat - concatenate files and print on the standard
output

Syntax: cat [file1] [file2] … [fileN]
girtsf@linux etc $ cat gentoo-release shells
Gentoo Base System version 1.4.16
# /etc/shells: valid login shells
# $Header: /home/cvsroot/gentoo-src/rc-scripts/etc/shells,v 1.5
2003/07/15 20:36:32 azarah Exp $
/bin/sh
/bin/bash
/bin/tcsh
/bin/csh
/bin/esh
/bin/ksh
/bin/zsh
/bin/sash
Helper utilities
 echo – displays a line of text
 Besides a program /bin/echo, also usually
built in the shell (takes precedence)

Syntax: echo [STRING] ...
girtsf@linux girtsf $ echo quick brown fox
quick brown fox
Can be used to display environment variables
girtsf@linux girtsf $ echo $HOME
/home/girtsf
Helper utilities
 wc - print the number of newlines, words, and
bytes in files

wc [options] [file1] [file2] … [fileN]
 By default, newlines, words and byte counts are
displayed
 Options



-c : print only byte count
-w : print only word count
-l : print only line count
Helper utilities
 Example use of wc:
girtsf@linux etc $ wc /etc/passwd
50
76 2257 /etc/passwd
lines words
bytes
girtsf@linux etc $ wc -l /etc/passwd
50 /etc/passwd
lines only
Helper utilities
 grep - print lines matching a pattern

grep PATTERN [file1] [file2] … [fileN]
 The lines that contain PATTERN are printed to
standard output.
 If no files are specified, input is taken from
standard input (more later).
 Advanced versions of grep allow using regular
expressions in PATTERN.
Helper utilities
 File “testfile” contains the following lines
girtsf@linux girtsf $ cat testfile
the quick brown
fox jumped over
the lazy dog
 We search for “the”:
girtsf@linux girtsf $ grep the testfile
the quick brown
the lazy dog
 Only lines containing the substring “the” are
printed.
Helper utilities
 Some useful parameters for grep:




-i : ignore case (“the” finds “the”, “The”, “THE”,…)
-l : output only filenames that match, not the contents
-B <n> : output also n lines before the matching line
-A <n>: output also n lines after the matching line
 See the man page (“man grep”) for all parameters
Helper utilities
 tee - read from standard input and write to standard output and files
 Syntax: tee [File1] [File2] .. [FileN]
 Example of tee taking user’s input from terminal and writing to 3 files:
girtsf@linux tmp
some string^D
some string
girtsf@linux tmp
some string
girtsf@linux tmp
some string
girtsf@linux tmp
some string
$ tee a b c
$ cat a
$ cat b
$ cat c
In red – my input,
ending with Control-D,
which is the EOF (End
of File) character.
This input is read as
standard input by tee.
Helper utilities
 Any program can be used as a helper program
 More examples later
Connecting utilities with shell
scripting
 Standard I/O
 I/O redirection to/from file
 I/O redirection using a pipe
 Backticks
Standard I/O
 Every process, when run, has 3 already open
data streams (file descriptors):



Standard input
Standard output
Standard error
Standard I/O
 When run interactively (from command line),
these streams are attached to the terminal they
are running from



Standard input is attached to user’s keyboard input
Standard output is attached to user’s terminal output
Standard error, similarly to output, is attached to
user’s terminal output
 Usually referred to as stdin, stdout, stderr.
Standard output & error
 “ls” command does not use input, but uses stdout, stderr.

The second line is the stdout from “ls” command:
girtsf@linux etc $ ls -l /etc/passwd
-rw-r--r-- 1 root root 2257 Oct 22 13:35 /etc/passwd

The second line is from stderr from “ls” command:
girtsf@linux etc $ ls -l /etc/asdfasdf
ls: /etc/asdfasdf: No such file or directory

Both stdout and stderr simultaneously:
girtsf@linux tmp $ ls -l /etc/passwd /etc/asdfasdf
ls: /etc/asdfasdf: No such file or directory
-rw-r--r-- 1 root root 2257 Oct 22 13:35 /etc/passwd
I/O Redirection to/from file
 By default, the 3 streams are attached to terminal
 This can be overridden when executing the
command and is called “redirection”
 “>” specifies that stdout is redirected to file
 “<“ specifies that stdin is taken from file
 “2>” specifies that stderr is redirected to file
I/O Redirection to/from file
 Syntax:
 <cmd> [ > <file1>] [ < <file2> ] [ 2> <file3> ]
 For those redirections that are specified, the
respective stream will be attached to the specified
file
 None, one, two or all three types can be specified
 If output file exists: > - replace file; >> - append to file
I/O Redirection to file
 Example of stdout redirection to file
girtsf@linux tmp $ ls -l /lib/ > direktorijas_saraksts
girtsf@linux tmp $ cat direktorijas_saraksts
total 4035
-rwxr-xr-x
1 root root
7488 Oct 6 12:33 cpp
drwxr-xr-x 13 root root
1024 Oct 25 15:57 dev-state
drwxr-xr-x
2 root root
1024 Jun 28 09:53 evms
drwxr-xr-x
2 root root
2048 Aug 23 15:25 iptables
...
I/O Redirection to file
 Example of stdout redirection to file
girtsf@linux tmp $ ls -l /asdf > direktorijas_saraksts
ls: /asdf: No such file or directory
girtsf@linux tmp $ cat direktorijas_saraksts
 The file is empty, as no output was sent to stdout,
as error message was send to stderr, which still
was attached to user’s terminal
I/O Redirection to file
 Example of stderr redirection to file
girtsf@linux tmp $ ls -l /asdfasdf 2> errlog
girtsf@linux tmp $ cat errlog
ls: /asdfasdf: No such file or directory
 Now stderr was redirected to file and file
contained the error message.
I/O Redirection to file
 Example of stdout, stderr redirection to file
girtsf@linux tmp $ ls -l /asdfasdf /lib 2>errlog >sar
girtsf@linux tmp $ cat errlog
ls: /asdfasdf: No such file or directory
girtsf@linux tmp $ cat sar
/lib:
total 4035
-rwxr-xr-x
1 root root
7488 Oct 6 12:33 cpp
drwxr-xr-x 13 root root
1024 Oct 25 15:57 dev-state
drwxr-xr-x
2 root root
1024 Jun 28 09:53 evms
drwxr-xr-x
2 root root
2048 Aug 23 15:25 iptables
...
I/O Redirection from file
 Example of stdin redirection

First, we create file “a” with the following content
the quick brown fox
jumped over a quick brown fox

Use wc (word count) by not supplying the file
name, but redirecting standard input
girtsf@linux tmp $ wc < a
2 10 50
I/O Redirection with pipes
 Task: given a file, output the total number of words
in those lines, that contain substring “the”.
 Example input:
girtsf@linux girtsf $ cat testfile
the quick brown
fox jumped over
the lazy dog
 Lines 1 and 3 match, total number of words = 6.
I/O Redirection with pipes
 Solution with redirection to files:


First find the lines, save them into temp file
Then use wc (word count) utility to count the number
of words
girtsf@linux girtsf $ grep the testfile > tmpfile
girtsf@linux girtsf $ wc –w < tmpfile
6
I/O Redirection with pipes
 Temporary file was used to redirect the standard
output of grep to file
 The standard input to wc was taken from
temporary file
 Easier way – connect the standard output of one
program to standard input of another one directly
I/O Redirection with pipes
 Syntax: program1 | program2 (| - pipe symbol)
 Called “piping output from one program to
another”
 This example:
girtsf@linux girtsf $ grep the testfile | wc -w
6
 No temporary files. Elegant!
Backticks
 Backticks – reverse apostrophes “`” (usually the
same key as tilde ~ character)
 Using backticks sub-commands are executed,
their result written in the place they are defined
 Example:
girtsf@linux tmp $ cd `echo /home`
girtsf@linux home $
Substituted with “/home”
Helper utilities
 We will examine the following utilities:





cut
sort
uniq
awk
sed
cut
 cut - remove sections from each line of files
 Syntax: cut [OPTION]... [FILE]...
 Options:



-d DELIM : use DELIM instead of TAB character
-f LIST : output only these fields (delimited by DELIM)
-c LIST : output only these characters
 See man page for more options
cut
 Example – output second word on each line:


Delimiter: space “ “
Fields: 2
girtsf@linux tmp $ cat a
the quick brown fox
jumped over a quick brown fox
girtsf@linux tmp $ cut -f 2 -d ' ' a
quick
over
cut
 Example – output characters 1-3, 5, 7-end

Use –c to choose the needed characters
girtsf@linux tmp $ cat a
the quick brown fox
jumped over a quick brown fox
girtsf@linux tmp $ cut -c 1-3,5,7- a
theqick brown fox
jume over a quick brown fox
sort
 sort - sort lines of text files

sort [OPTION]... [FILE]...
 Writes sorted concatenation of all FILE(s) to standard
output.
 Interesting options:


-r : reverse
-n : compare according to string numerical value
 See man page for more options
sort
 sort - sort text file reversed
girtsf@linux tmp $ cat a
fish
dog
animal
bird
girtsf@linux tmp $ sort -r a
fish
dog
bird
animal
sort
 Sort numeric file (as text)
girtsf@linux tmp $ cat a
5412 this line should go last
998 this line should go second
50 this line should go first
999 this line should go third
girtsf@linux tmp $ sort a
50 this line should go first
5412 this line should go last
998 this line should go second
999 this line should go third
sort
 Sort numeric file as numbers
girtsf@linux tmp $ cat a
5412 this line should go last
998 this line should go second
50 this line should go first
999 this line should go third
girtsf@linux tmp $ sort -n a
50 this line should go first
998 this line should go second
999 this line should go third
5412 this line should go last
uniq
 uniq - remove duplicate lines from a sorted file

uniq [OPTION]... [INPUT [OUTPUT]]
 Discards all but one of successive identical lines
from INPUT (or standard input), writing to
OUTPUT (or standard output).
 Can be used together with sort, to get file without
duplicate lines.
uniq
Just sorted:
sort | uniq:
$ cat a | sort
bird
bird
dog
dog
fish
fish
fly
$ cat a | sort | uniq
bird
dog
fish
fly
awk
 gawk (GNU awk) - pattern scanning and processing
language.
 Gawk is the GNU Project's implementation of the AWK
programming language. It conforms to the definition of
the language in the POSIX 1003.2 Command Language
And Utilities Standard. This version in turn is based on
the description in The AWK Programming Language, by
Aho, Kernighan, and Weinberger, with the additional
features found in the System V Release 4 version of
UNIX awk.
awk
 Complete language interpreter



Variables
User defined functions
…
 Useful for small one-liners
 Just some examples will be given
 See man page or search for tutorials on the net
awk
Task: sum all the numbers in the file:
$ cat a
1
2
3
first field
4
5
$ cat a | awk '{ sum += $1 } END { print sum }'
15
executed on every line
executed at the end
awk
 Sum 2nd field (separated by colons) of those lines, that contain
letter “a”
girtsf@linux tmp $ cat a
zzz:1:a
field
zzz:2:b
delimiter
zzz:3:b
zzz:4:b
zzz:5:a
girtsf@linux tmp $ cat a | awk -F ':' '{ if(/a/)
sum += $2; } END { print sum }'
6
sed
 sed – stream editor
 A stream editor is used to perform basic text
transformations on an input stream (a file or input from
a pipeline). While in some ways similar to an editor
which permits scripted edits (such as ed), sed works by
making only one pass over the input(s), and is
consequently more efficient.
 Simpler than awk, smaller feature set.
 Just some examples will be given.
 See man page or search for tutorials on the net.
sed
 Replace some substring with another
$ cat a
bird barks
mouse runs
$ sed 's/barks/flies/' < a
bird flies
mouse runs
Regular expression
sed
 Replace some characters with others

Replacing ‘b’ with ‘Q’, ‘i’ with ‘X’
girtsf@linux tmp $ cat a
bird barks
mouse runs
girtsf@linux tmp $ cat a | sed 'y/bi/QX/'
QXrd Qarks
mouse runs
Advanced example 1
 Calculate total bytes transferred in Apache log file.


First, take only successful lines (containing error code 200)
Sum up byte field
 Line format:
159.148.123.123 - - [28/Oct/2004:18:11:36 +0300] "GET
/somefolder/file.php HTTP/1.1" 200 127602 "-"
"Opera/7.54 (X11; Linux i686; U) [en]"
Advanced example 1 cont.
$ cat access_log | grep ' 200 ' | awk '{ bytes +=
$10 } END { print bytes }'
1105653994
 Cat file
 Grep for “ 200 “
 Sum up 10th column, output it at the end
Advanced example 2
 Calculate number of hits per remote host in
Apache log file, most active hosts first.
 Line format:
159.148.123.123 - - [28/Oct/2004:18:11:36 +0300]
"GET /somefolder/file.php HTTP/1.1" 200 127602
"-" "Opera/7.54 (X11; Linux i686; U) [en]"
Advanced example 2
$ cat access_log | cut -d ' ' -f 1 | sort | uniq -c
| sort –n -r
 First, cut out the host part (1st field), sort it
 get the number of repeated lines before the line (uniq –c : prefix
lines by the number of occurrences),
 sort it numerically, reversed so that largest number comes first
 Output:
348698
123485
12313
...
159.148.111.222
159.148.48.54
80.123.123.4
Helper utilities
 Some more utilities that can be useful






head, tail - output the first/last part of files
basename - strip directory and suffix from filenames
bc - an arbitrary precision calculator
sleep – sleep specified number of seconds
tr – translate or delete characters
true, false – always return success/error code
 Read the man pages
Tips for working in a shell
 Up arrow – repeats the previous command
 history – internal bash command that shows command
history
 Use script to make a typescript of terminal session
 CTRL-R and a few chars recalls last command that
contains these chars:

(reverse-i-search)`re': grep text file*
The ABCs of Unix













A is for awk, which runs like a snail
B is for biff, which reads all your mail
C is for cc, as hackers recall
D is for dd, the command that does all
E is for emacs, which rebinds your keys
F is for fsck, which rebuilds your trees
G is for grep, a clever detective
H is for halt, which may seem defective
I is for indent, which rarely amuses
J is for join, which nobody uses
K is for kill, which makes you the boss
L is for lex, which is missing from DOS
M is for more, from which less was begot













N is for nice, which really is not
O is for od, which prints out things nice
P is for passwd, which reads in strings twice
Q is for quota, a Berkeley-type fable
R is for ranlib, for sorting a table
S is for spell, which attempts to belittle
T is for true, which does very little
U is for uniq, which is used after sort
V is for vi, which is hard to abort
W is for whoami, which tells you your name
X is, well, X, of dubious fame
Y is for yes, which makes an impression, and
Z is for zcat, which handles compression
Another
UNIX
command
refference
 Use man pages
for further
details
Shell scripts as files
 Everything that can be called from command line,
can also be called from shell script
 Shell Script is series of commands written in plain
text file.
 Shell script is just like batch file is MS-DOS but
have more power than the MS-DOS batch file.
Running a shell script
 As a parameter to shell interpreter

bash some_script.sh
 Specifying interpreter on first line
First line:
#!/bin/bash
 Make it executable (chmod +x some_script.sh)
 ./some_script.sh

Intercative shell coniguration files
Basics
 Interpreted line by line
 The same effect when entering the lines one by
one in interactive shell
Sample shell script
Interpreter to be used
#!/bin/bash
# comment line
echo "what a fine day: "
Regular commands to execute
date
 Output, when called by “./test.sh”:
what a fine day:
Thu Oct 28 23:37:39 EEST 2004
Variables
 Sample “hello world” with variables
#!/bin/bash
STR="Hello World!"
echo $STR
 When assigning, no $ is used
 When getting the contents – use $
 No data types – string, number, character, all the same
 No declaring, just assign
Another sample shell script
#!/bin/bash
DATE=`date +%Y%m%d`
WHAT='/home/girtsf'
DEST="/backups/$DATE.tgz"
tar cvzf $DEST $WHAT
 Results in calling:
tar cvzf /backups/20041028.tgz
/home/girtsf
Conditionals
 Example:
#!/bin/bash
T1="foo"
T2="bar"
if [ "$T1" = "$T2" ]; then
echo expression evaluated as true
else
echo expression evaluated as false
fi
Command line arguments
 Automatically defined variables





$0 – contains shell script name
$1 – contains first argument
$2 – 2nd
…
$* - contains all arguments as a string
Command line arguments &
conditionals example
#!/bin/sh
returns error code
#
usually 0 – no error
#Script to print file
#
if executes branch if
if cat $1
command returns 0
then
echo -e "\n\nFile $1, found and
successfully echoed"
fi
Comparisons
 Either “test <expression>” or “ [ <expression> ] “


if test $1 -gt 0
if [ $1 -gt 0 ]
 Numeric comparisons:


-eq, -ne equal/not equal
-lt, -le, -gt, -ge : less than, less than or equal, greater
than, greater than or equal
Comparisons
 String comparisons





string1 = string2
string1 != string2
string1
-n string1
-z string1
string1 is equal to string2
string1 is NOT equal to string2
string1 is NOT NULL or not defined
string1 is NOT NULL and does exist
string1 is NULL and does exist
File tests
 -s file
 -f file
directory
 -d dir
 -w file
 -r file
 -x file
Non empty file
File exist or normal file and not a
Directory exist and not a file
Is writeable file
Is read-only file
File is executable
Logical Operators
 ! expression Logical NOT
 expression1 -a expression2
 expression1 -o expression2
Logical AND
Logical OR
Another example
#!/bin/sh
# Script to test if..elif...else
#
if [ $1 -gt 0 ]; then
echo "$1 is positive"
elif [ $1 -lt 0 ]
then
echo "$1 is negative"
elif [ $1 -eq 0 ]
then
echo "$1 is zero"
else
echo "Opps! $1 is not number, give number"
fi
Arithmetic expansion
 Arithmetic expansion allows the evaluation of an
arithmetic expression and the substitution of the result.
The format for arithmetic expansion is:

$((expression))
A=5
B=4
C=$(($A*$B))
echo $C
Loops: for
for { variable name } in { list }
do
execute one for each item in the list until the
list is not finished (And repeat all statement
between do and done)
done
for i in 1 2 3 4 5
do
echo "Welcome $i times"
done
Loops: for
for (( expr1; expr2; expr3 ))
do
repeat while expr2 is true
done
for (( i = 0 ; i <= 5; i++
do
echo "Welcome $i times"
done
))
Using for
 You can use for together with file name expansion to
perform the same action for several files
#!/bin/sh
for x in *txt;
do
cat $x
done;
Loops: while
while [ condition ]
do
command1
command2
command3
....
done
Many more features
 See man page
 Linux Shell Scripting Tutorial: A Beginner's
handbook:

http://www.freeos.com/guides/lsst/
Word guessing game
 Source:

http://www.ltn.lv/~guntis/unix/mini.txt
+-----|/ |
|
o
|
O
| /
|
MATER_AL
Juusu mineejums: i
Main part
izveleties_vardu
stripas
gaj=0
while true;
do
zimet_karatavas $gaj
echo $v
echo -n "Juusu mineejums: "
read iev
gajiens $iev
if [[ $v == $vards ]]; then
uzvara; exit
fi
if [[ $gaj -eq 10 ]]; then
zaude; exit
fi
done;
Getting a random word
izveleties_vardu()
{
local sk r
if [[ -e /usr/share/dict/words ]];
then
echo Njemu vienu nejaushu vaardu no /usr/share/dict/words!
sk=`cat /usr/share/dict/words|wc -l`
r=$(($RANDOM % $sk + 1))
vards=`tail +$r /usr/share/dict/words|head -1|tr a-z A-Z`
else
echo /usr/share/dict/words nav atrasts, njemu nokluseeto vaardu!
vards="KARATAVAS"
fi
sleep 1
}
Convert letters to underscores
stripas()
{
local i
i=${#vards}
v=
while [[ $i>0 ]];
do
i=$(($i-1))
v=${v}_
done
}
Comparison part
while [[ $i < $l ]];
do
t=${vards:$i:1}
if [[ $t == $b ]];
then
v2=${v2}$b
ir=$(($ir+1))
else
v2=${v2}${v:$i:1}
fi
i=$(($i+1))
done