Bash Check If String Starts With Character

Also thanks for pointing out the issue with the set command and quotes. Lets try to validate with an example. Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. The while construct is written in a way that will execute with a condition; if a file is given, it will proceed until the read exhausts. # Bash permits integer operations and comparisons on variables #+ whose value consists of all-integer characters. GitHub Gist: instantly share code, notes, and snippets. In fact, the bash totally ignores them. org $ cat bash. 15+ String manipulation examples for Shell scripting But if you want to check if the variable is defined or not it’s bit tedious job to check every time whether. For example: randstring=caboosel1 I want to know if this string contains any of the following: 1 (one), l (lower case L), 0 (zero) or O (upper case O). Escaping will suppress a special meaning of meta characters and therefore meta characters will be read by bash literally. When you try to evaluate if VAR1 contains the substring in VAR2, you get false result in Build Forge (command section). New variables to support the bash debugger: BASH_ARGC, BASH_ARGV, BASH_SOURCE, BASH_LINENO, BASH_SUBSHELL, BASH_EXECUTION_STRING, BASH_COMMAND i. -i: If the -i option is present, the shell is interactive. Thanks to this environment, it’s actually possible to write a Bash shell script on Windows and run it. The ${var:offset} and ${var:offset:length} constructs can be used to obtain a substring. It's easy to leverage that in your case: just put your string into an array without quoting it - bash will use word splitting to separate the individual elements. Hi, I need to find whether the first character in a line is a alphabet or a number. These options must appear on the command line before the single-character options to be recognized. This is what I have so far. Now this one may seem a bit odd to you at first. Here I want to pass a string to the script and want the script to check if the string has only [SOLVED] Bash Shell Script to check if a string has only alphabets and digits. Once the basic R programming control structures are understood, users can use the R language as a powerful environment to perform complex custom analyses of almost any type of data. Handling Text in R Text Strings. Is true even if file is a directory. Usually though in a bash script you want to check if the argument is empty rather than if it is not empty, to do this you can use the -z. Numeric and String Comparison. Releases with a different major version number (releases are major. Red Hat Enterprise Linux 3 CentOS Linux 3 Red Hat Enterprise Linux 4 CentOS Linux 4 Oracle Linux 4 Integer overflow in the format string functionality (Perl_sv_vcatpvfn) in Perl 5. Remove files with names containing strange characters such as spaces, semicolons, and backslashes in Unix. Thus far, we have learned about literal characters, character classes, and the dot. Regular Expression For Json String. # Awk numbers first character of string as 1. If its a alphabet i should sort it based on the ASCII value. bash Cheat Sheet from gregcheater. If this option is not found, the first parameter of getopt that does not start with a ‘-’ (and is not an option argument) is used as the short options string. In Bash, a variable may store a character string, a number or even the output of a command. Bash case statements are generally used to simplify complex conditionals when you have multiple different choices. This skips words between balanced pairs of quotes, words where the first character is quoted with a `\', and other backslash-escaped characters. When writing shell scripts you may be in a situation where you need to pass multiline block of text or code to an interactive command. You should remember that shell scripting is less of a language and more of a collection of commands. The string is empty "". Using Bash's regular expressions Bash has quietly made scripting on Unix systems a lot easier with its own regular expressions. Most of the time the output of a command ends with the newline character. A quick run down on how you can use regular expressions in your own programs to give you more power over searching and substituting text. If you are using bash, you can use the builtin “[[“ and do this: [code]$ fullstring="The quick brown fox jumps over the lazy dog" $ start_string="The" $ if. Left String - Extract characters from the beginning of a string Description: Similar to the Left function in VB a batch script can return a specified number of characters from the left side of a string by specifying a substring for an expansion given a position of 0 and a length using :~ while expanding a variable content. A process is program (command given by user) to perform specific Job. Executables must start with #!/bin/bash and a minimum number of flags. The second character is the character which signifies `quick substitution' when seen as the first character on a line, normally ‘ ^ ’. To use this run: sh -n your_script If this returns nothing then your program is free of syntax errors. character between a & g: Anchors ^abc$ start / end of the string Regex Tester isn't optimized. class json. The last example is wrong, and might be why Dinesh and I were getting wrong results. You can adjust the default so that it only returns a string with 8 printable characters or 12 printable characters. printf '%s' to prevent printf from expanding backslash escapes: bash printf literal verbatim string; grep -q prevents echo of matches to stdout: How to check if a file contains a specific string using Bash; grep -E enables extended regular expressions, which we need for the ^. 0 and later interrupt the list as if the shell received the interrupt; previous versions continue with the next command in the list. I've been. Usually, you can tell a string because it will be enclosed in (double) quotation marks. The system can't decide which of these filenames we wanted to type, but it does. Users enter responses to prompts, file names are generated, and commands produce output. Example-3: Using shorthand '+=' operator to combine string. Use set to set shell options so that calling your script as bash does not break its functionality. To learn how to configure your YAML pipeline the way you need it to work, see conceptual topics such as Build variables and Jobs. Reading (quoting) a variable. If set is just a single period (. txt) * Matching. The term string is used generically to refer to any sequence of characters; typical examples of strings might be a line of input or a single argument to a command. Perl has long been an extremely popular choice for text. if condition to check if actual date exists as string in file? Does downing a character at the start of. Escaping will suppress a special meaning of meta characters and therefore meta characters will be read by bash literally. The minor differences are the treatment of escaped characters and new line character. The following are allowed wild card characters in first string. Check the given string is palindrome or not - cut the files vertically character or. linux,bash,rhel. All of us are very familiar with strings in programming languages like C. bash string substitution problem If this is your first visit, be sure to check out the FAQ by clicking the link above. If the substring is not found in string, FIND returns a value of 0. By default, the driver converts a Control-D character at the start of a line into an end-of-file indicator. When you run the same script in a Linux bask shell, you get true as result. In this section of our Bash Scripting Tutorial we'll look at the different loop formats available to us as well as discuss when and why you may want to use each of them. Command substitution allows the output of a command to replace the command itself. Here a listed few of many ways how to extract number from a string. Special Characters. [Note - since I compare shells, it can be confusing. The search begins at the first character position of this string and continues through the last character position. First released in 1989, it has been used widely as the default login shell for most Linux distributions and Apple's macOS Mojave and earlier versions. This can be used to decode a JSON document from a string that may have extraneous data at the end. The FIND function searches string for the first occurrence of the specified substring, and returns the position of that substring. But only a few may be knowing about customizing the Bash prompt. This article is part of the on-going bash tutorial series. To use this run: sh -n your_script If this returns nothing then your program is free of syntax errors. Identify String Length inside Bash Shell Script ${#string} The above format is used to get the length of the given bash. In this tutorial on Bash scripting, we are going to learn to do comparisons. txt Bash Scripting Tutorial Guide linuxconfig. I am searching a log file and need only the first 2 occurances of text which comes after (note the space) "string " and before a ",". Join GitHub today. CVE version: 20061101 ===== Name: CVE-1999-0002 Status: Entry Reference: BID:121 Reference: URL:http://www. To have a search pattern check at the start of the beginning of a string, James shows anchoring within Regular Expressions. Match string not containing string Check if a string only contains numbers Match elements of a url Validate an ip address Match or Validate phone number Match an email address Match dates (M/D/YY, M/D/YYY, MM/DD/YY, MM/DD/YYYY) Empty String Not Allowing Special Characters Checks the length of number and not starts with 0 Match html tag Match a. Here I am trying to check if a string ends with def given my string is abcdef. If statements (and, closely related, case statements) allow us to make decisions in our Bash scripts. If its a number i should sort it numerically. Three types of wildcards are used with Linux commands. Each iteration starts from the character immediately after the last character of any match string. I need an if statement for a Linux bash shell script, to determine if a string contains one or more of a given set of characters. In order to build a regular expression to check if String is number or not o r if String contains any non digit character or not you need to learn about character set in Java regular expression, Which we are going to see in this Java regular expression example. org $ cat bash. I know that in those files resources are declared as such: resource "service_n. One can check that with It not only works in bash but also. It is true if the variable has a string set. • A script is a list of system commands stored in a file. The last example is wrong, and might be why Dinesh and I were getting wrong results. 6 Bash Style Guide and Coding Standard 1 Length of line The total length of a line (including comment) must not exceed more than 88 characters. If other code forces the input to be a single character, it doesn't matter, but what the cooe actually does is to check that there is at least one matching character in a potentially longer string. Regular Expression For Json String. Along with the single character shell command-line options (See section The Set Builtin) there are several other options that you can use. stop - Index at which to stop searching. -z string (conditional expression) will return true if the length of string is zero. Tutorial - Bash Strings Equal: To check if given two strings are the same in value or not. I know that in those files resources are declared as such: resource "service_n. Strings can be handled efficiently using string functions in bash shell. sh String=23skidoo1 # 012345678 Bash # 123456789 awk # Note different string indexing system: # Bash numbers first character of string as 0. Then init=${string:0:1} is what you want to test. If this login name is the null string, the tilde is replaced with the value of the `HOME' shell variable. We come across files and folders name very regularly. This would remove the string GACTACACGTAGTAT from the second, fourth, sixth, eighth lines (etc). If the substring is not found in string, FIND returns a value of 0. Refer to our earlier article on bash { } expansion. Thus searching in cross direction can be avoided and the file can be printed with the usual width of paper. Bash Strings Equal – In this tutorial, we shall learn how to check if two strings are equal in bash scripting. Bash Shell: Find Out If a Variable Is Set or Not; Bash shell find out if a variable has NULL value OR not; Bash Shell Find Out If a Variable Is Empty Or Not; Bash Shell Count Number of Characters In a String or Word; Bash check if string starts with character such as # Use BASH nullglob To Verify *. Apologize in advance to ask a very lame question. Its used to match any character that occurs in our search term. Regular Expressions are sets of characters and/or metacharacters that match (or. This can save a lot of work when parsing replies to shell-script questions. -z s1 Check if s1 has size 0. This tutorial aims to help the reader understanding conditions in bash, and provides a […]. Let us start with an example Check if var1 have a string which starts with a. Le's say we have a string "Hello Bash":. This is done with bash parameter expansion. This is the default structure of the bash prompt on many Linux systems and is displayed every time you log in using a terminal. This type of variable (with the exception of auto_resume and histchars) is defined in CAPITAL LETTERS. txt) * Matching. Bash is intended to be a conformant implementation of the Shell and Utilities portion of the IEEE POSIX specification (IEEE Standard 1003. If none of the characters in the tilde-prefix are quoted, the characters in the tilde-prefix following the tilde are treated as a possible LOGIN NAME. A large number of shell instances are started as part of the Ubuntu boot process. c:3577 msgid "FLUSHQ, flushes the current server's send queue" msgstr "" #: src/common. 2 get_frame_register_bytes %s/lockfile shoptionletters. Because these characters have special meaning in regular expressions, we need to "escape" these characters to tell grep that we do not wish to use their special meaning in this case. c:3572 msgid "EXECSTOP, sends the process SIGSTOP" msgstr "" #: src/common/outbound. However, it is rather large and slow to start up and operate by comparison with dash. \b matches here, because the T is a word character and the character before it is the void before the start of the string. ADDUSERS Add or list users to/from a CSV file. -z string (conditional expression) will return true if the length of string is zero. character between a & g: Anchors ^abc$ start / end of the string Regex Tester isn't optimized. The default encoding for Python source code is UTF-8, so you can simply include a Unicode character in a string literal:. For example, to move three characters from the beginning of the search, you'd use /string/s+3 or /string/b+3 -- "s" for "start" or "b" for "begin. From the following article, you'll learn how to print lines between two patterns in bash. txt" exists or a file called "file1. However, it is rather large and slow to start up and operate by comparison with dash. Variables · Functions · Interpolation · Brace expansions · Loops · Conditional execution · Command substitution · One-page guide to Bash scripting. This can be done with the following commands: $ mkdir trash $ cp * trash $ rm -rf trash $ mkdir trash • Instead of having to type all that interactively on the shell, write a shell program. This symbol matches any number of any characters. –Number, character or string • Use option --help to check usage of commands. CVE version: 20061101 ===== Name: CVE-1999-0002 Status: Entry Reference: BID:121 Reference: URL:http://www. The engine does not advance to the next character in the string, because the previous regex token was zero-length. For example, we can use dot like $ grep "d. s1 Check if s1 is not the empty string. Since regular expressions work with text, a regular expression engine treats 0 as a single character, and 255 as three characters. Bash check if string starts with character such as # last updated December 14, 2018 in Categories BASH Shell , Linux , UNIX M y bash shell script read a config file line-by-line using a bash while loop. org, a friendly and active Linux Community. How can I read random bytes from /dev/urandom in bash? Stack Exchange Network Stack Exchange network consists of 175 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Setting Option Compare is a module level decision effecting statement level results. Write a function or program that takes two words as input and outputs variants of the popular English tongue-twister "How much wood would a woodchuck chuck if a woodchuck could chuck wood?". html and introduction-to-firefox. Simple Bash if/else statement Please note the spacing inside the [ and ] brackets! Without the spaces, it won't work!. bash command for removing special characters from string Just starting out and have a question? If it is not in the man pages or the how-to's this is the place. How do I check if variable begins with # in bash shell scripting running on a Linux or Unix-like operating systems? Introduction – In bash, we can check if a string begins with some value using regex comparison operator =~. We have selected expected 70 shell scripting question and answers for your interview preparation. This tutorial aims to help the reader understanding conditions in bash, and provides a […]. The task once again demonstrates that anchors are not characters, but tests. So there’s a match. The positional parameters are now assigned before running the shell startup files, so startup files can use [email protected] s. eof (end-of-file character) start with a space or tab. Refer to our earlier article on bash { } expansion. The shell also has a mode to check for syntax errors without actually executing the program. VI and VIM Linux editor tutorial of advanced editing features and tricks. Usually though in a bash script you want to check if the argument is empty rather than if it is not empty, to do this you can use the -z. Example: ls e?. Parsing Strings with split Parsing parsing dividing a string into tokens based on the given delimiters token one piece of information, a "word" delimiter one (or more) characters used to separate tokens. A regular expression is a string of characters that define the pattern or patterns you are viewing. Linux Bash Shell script 4/29/2014 Linux Bash Shell script 1 2. The result of var1 = var2 where Var1 and var2 only differ in the use of capitals depends on the Option Compare Setting. This tutorial covers advanced use, tagging, vim plugins and integration with cscope. Here, we've used quotations since the value of our variable contains a space. ) character then it will just enumerate the directory tree. Loops allow us to take a series of commands and keep re-running them until a particular situation is reached. Then init=${string:0:1} is what you want to test. Bash can be used to perform some basic string manipulation. Handling Text in R Text Strings. txt Bash Scripting Tutorial Guide linuxconfig. Regular expreesion in Linux Bash and KSH Shells -match a group of characters. Bash is surprisingly configurable, and, by the time you finish reading this article, you'll have an environment more comfortable for you. You may have to register before you can post: click the register link above to proceed. Tag: regex,perl,bash,shell i am an enthusiast of computers but never studied programming. The Bash shell supports a lot of special characters for customizing the prompt. If other code forces the input to be a single character, it doesn't matter, but what the cooe actually does is to check that there is at least one matching character in a potentially longer string. For example I have a string: /some/directory/file I want this to return 1,. txt I'd like to apply to to only every other line, starting with the second. When writing shell scripts you may be in a situation where you need to pass multiline block of text or code to an interactive command. You are currently viewing LQ as a guest. #endsWith check if a word is at the end of a string endsWith string endToCheck ? depth # depth >> where to start the search from endsWith " bash " a 2 # returns 1 for false or 0 for true #isInteger check if a value is an integer. Currently it holds \[email protected]\h:\w\$ special bash characters. These notes are called comments. inarr=(${a}) If the delimiter is not space and delimiter is a single character or a string consisting of 1 or more of the characters, set the IFS like. If the character is upper case, we convert it to lower case and append it to the result. Check bash manual page with $ man bash. s1 Check if s1 is not the empty string. Seen together: Awk will match a regular expression with "Linux" at the start of the first column. >>> input = 'viewsby' >>> input[0]. You can adjust the default so that it only returns a string with 8 printable characters or 12 printable characters. Filed under: Server—Tags: bash, sed, shell Sed is a stream editor, meaning you can search and replace strings in files and use regex if needed. Checking for substrings. Need help? Post your question and get tips & solutions from a community of 429,300 IT Pros & Developers. As indicated in the comments, you need to provide "something" to your while loop. Usually though in a bash script you want to check if the argument is empty rather than if it is not empty, to do this you can use the -z. Bash also incor- porates useful features from the Korn and C shells (ksh and csh). The Start-AzureStorageBlobCopy cmdlet starts to copy a blob. (It you want a bookmark, here's a direct link to the regex reference tables). so you can write Perl scripts, for example, with #!/usr/bin/perl in the header of the script file. I know that in those files resources are declared as such: resource "service_n. This is called quoting. The following example demonstrates using a function to extract the digits from a string of a variety of characters. s1 != s2 Check if s1 is not equal to s2. Shell = Check if variable begins with # As you accepted a answer which involves a bash characters of parameter starting at the character specified by offset. In applications written for ASCII or ISO 8859, a far more common use of strlen is to predict the number of columns that the cursor of the terminal will advance if a string is printed. The system can't decide which of these filenames we wanted to type, but it does. So we've already seen an example of dot which. This is risky business indeed. Parameters can be expanded to just part of their contents, either by offset or by removing content matching a pattern. Introduced with version 2 of Bash. Pipelines are made. Since the string is delimited by double-quotes, you need to escape the quote that is part of the string, in order to tell awk to keep processing the rest of the string. Regular Expressions are sets of characters and/or metacharacters that match (or. Refer to our earlier article on bash { } expansion. linuxconfig. 6 Perl allows attackers to overwrite arbitrary memory and possibly execute arbitrary code via format string specifiers with large values, which causes an. 4 Upstream Status: Already in upstream patch repo Origin: Upstream Description: This patch. An expression is a string of characters. -c string: If the -c option is present, then commands are read from string. Bash Shell Count Number of Characters In a String or Word; HowTo Display Text Files In a Shell Script; Linux / Unix sed: Delete Word From File / Input; Bash check if string starts with character such as # Bash Shell: Find Out If a Variable Is Set or Not; Freebsd changing password; Bash Script Replace Empty Spaces String. The randomness comes from atmospheric noise, which for many purposes is better than the pseudo-random number algorithms typically used in computer programs. If the character is upper case, we convert it to lower case and append it to the result. Is true even if file is a directory. (It you want a bookmark, here's a direct link to the regex reference tables). c:3572 msgid "EXECSTOP, sends the process SIGSTOP" msgstr "" #: src/common/outbound. As an MPE user, you may find regular expressions difficult to use at first. In order to build a regular expression to check if String is number or not o r if String contains any non digit character or not you need to learn about character set in Java regular expression, Which we are going to see in this Java regular expression example. Currently it holds \[email protected]\h:\w\$ special bash characters. The string is empty "". A regular expression is a string of characters that define the pattern or patterns you are viewing. A quick run down on how you can use regular expressions in your own programs to give you more power over searching and substituting text. So I decided to write my own version of this essay - as a gentle argument to a current C shell programmer from a former C shell fan. Unix Command Dictionary (Hanson) Replace a string of characters by `[string]' in ' characters starting at the cursor and puts them into the default. return a substring of VAR where the smallest string (starting from the Check out Readable. Not only will this work to check for a character, but it will also work to check for a substring, or a consecutive sequence of characters in a larger string. I am searching a log file and need only the first 2 occurances of text which comes after (note the space) "string " and before a ",". set caption = "Processing NGC 2345. CVE version: 20061101 ===== Name: CVE-1999-0002 Status: Entry Reference: BID:121 Reference: URL:http://www. Shell = Check if variable begins with # As you accepted a answer which involves a bash characters of parameter starting at the character specified by offset. Bash uses the value formed by expanding the rest of parameter as the new parameter; this is then expanded and that value is used in the rest of the expansion, rather than the expansion of the original parameter. s1 Check if s1 is not the empty string. If the line starts with a "%" then I'm using the C shell. Lastly, press Ctrl-D. Embedded newlines are not deleted, but they may be removed during word splitting. This is a great way to test if a bash script was given arguments or not, as a bash scripts arguments are placed into variables $1, $2, $3 and so on automatically. The obvious control characters are stuff like line feed (newline), backspace and bell beep, but more specific commands are given as sequences of characters, starting with the ESC character (code 27 in decimal, 0x1b in hex. Benefits of Regular Expression: The following are benefits (not all included) of use of Regular Expression. GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Bash - newline and other escape character in string; Bash - pass all arguments from one script to another; Bash - set default value if a variable is empty; Bash - variables in double quotes vs without quotes; Bash associative array tutorial; Bash check if file begins with a string; Bash shell - check if file or directory exists. Furthermore, no string argument can be specified with the flags for sending null characters or breaks. The easiest way is if you are working on bash shell - as bash will get the job done without the help of any external utilities. -z string (conditional expression) will return true if the length of string is zero. txt" exists or a file called "file1. Regular Expression to Check if a string only contains numbers. 0, the language’s str type contains Unicode characters, meaning any string created using "unicode rocks!", 'unicode rocks!', or the triple-quoted string syntax is stored as Unicode. Simple Bash if/else statement Please note the spacing inside the [ and ] brackets! Without the spaces, it won't work!. Let’s try out a few examples. One can check that with It not only works in bash but also. The following example sets a variable and tests the value of the variable using the if statement. '\t' is supported as a regular expression. The TEST-COMMAND often involves numerical or string comparison tests, but it can also be any command that returns a status of zero when it succeeds and some other status when it fails. 0 bundled, but Python users can update to a more recent compatible version if one is available. -z string (conditional expression) will return true if the length of string is zero. When you run the same script in a Linux bask shell, you get true as result. We hope you will now start writing your own shell scripts. If you start typing something bash will complete as far as it can, then will wait for you to complete the path, command or file name. Like in the second string, the capturing group grabs the a and the b matches. This regex means we are looking for a word that starts with 'd', ends with 'g' & can have any character in the middle in the file named 'file_name'. Regular Expression For Json String. To discover this new language I wanted to create a script which downloads and stores the "tip of the day" from Raspberry Pi website. This is normally done automatically by the system when the user first logs in. Bash Hello World Example Bash is a shell used on Unix-like operating systems. The FIND function searches string for the first occurrence of the specified substring, and returns the position of that substring. With 8 bits converted to three characters and each character stored as 1-4 bytes you might use up to 12 bytes (or even more in some cases) for each byte of information. Note that since bash 3. Often case statement lets you express a series of if-then-else statements that check single variable for various conditions or ranges in a more concise way. In bash, strings can be print with different formats including different front or background colors, blink, bold or hide etc. So there’s a match. Tutorial - Bash Split String: Split a string into tokens based on a single character delimiter or another string as a delimiter. Regular Expressions are sets of characters and/or metacharacters that match (or. Its really vital for all system admin to know scripting or atleast the basics which in turn helps to automate many tasks in your work environment. Numeric and String Comparison. I have to validate if a value of the variable starts with "efgh&quo | The UNIX and Linux Forums. The changes can be done "in place" or save the modified content to a renamed file. Next James introduces sed, a stream editor used to perform basic text transformations. These options must appear on the command line before the single-character options to be recognized. When writing shell scripts you may be in a situation where you need to pass multiline block of text or code to an interactive command. com/bid/121 Reference: CERT:CA-98. *+?…etc are taken literatlly. If either str or expression is a cell array of character vectors or a string array, and the other is a character vector or a string scalar, the output is a cell array of row vectors. Change the behavior of bash where the default operation differs from the POSIX standard to match the standard (posix mode). I know that in those files resources are declared as such: resource "service_n. You can easily combine string variables in bash. This tutorial covers advanced use, tagging, vim plugins and integration with cscope. It doesn't interrupt (halt. To extract all characters in a string after a dot (. This does not match any character. Then the wildcards around the condition are wrong. Shell Command Line Options. In this quick tip I am going to show you to delete or copy files with names that contain strange characters on Linux. To use this run: sh -n your_script If this returns nothing then your program is free of syntax errors. C# / C Sharp Forums on Bytes. If expression evaluates to TRUE, PHP will execute statement, and if it evaluates to FALSE - it'll ignore it. false-text) Specifies a ternary expression. With the help of isdigit() function we can check if a string start with number or not. All of the specified characters and ranges will be used concurrently (i. The engine first matches the ^ (input start), yes it’s there, and then immediately the end $, it’s here too. In the latter instance, the character between "new" and "file" is a space. In fact, the bash totally ignores them. The first is the line count, the second is the word count, and the third is the character count. One can test that a bash variable starts with a string or character in bash efficiently using any one of the following. Parameters can be expanded to just part of their contents, either by offset or by removing content matching a pattern. For example, P$ regex will match P at the end of. But with this script i have some problem when I enter from character from 'b' to 'z' --> result is uppercase.