![]() ![]() ![]() script.Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Predefined Attributes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search Save the script, give the execute permissions and execute: chmod +x script.sh. #!/bin/bashĮcho "Here are the Strings with the Pattern '$PATTERN':"Įcho "Error: The Pattern '$PATTERN' was NOT Found in '$FILE'" If it doesn’t exist we will print the error message and stop the script. If it exists, we will print all the strings that contain the pattern. Let’s check if the pattern exist in the file. Output: Error: The Pattern Does Not Exist BASH Script grep -q 'PATTERN' 'FILE' || echo "Error: The Pattern Does Not Exist" grep -q 'ANOTHER_ONE_PATTERN' 'SOME_FILE' & echo $?Ĭhecking if the string presents, and printing the error message if it doesn’t. ![]() The next example shows that ‘ANOTHER_ONE_PATTERN’ doesn’t present in ‘SOME_FILE’. grep -q 'SOME_PATTERN' 'SOME_FILE' & echo $? The following example shows that ‘SOME_PATTERN’ presents in ‘SOME_FILE’. Here are some examples of checking if the string, that contains some pattern, presents it the file. The exit status is 1 (false) if the pattern was not found.The exit status is 0 (true) if the pattern was found.You can use command exit status in the shell script to display an error message or perform some sort of action. Each Linux command returns a status when it terminates normally or abnormally It can be done with the help of ‘exit status codes’. Sometimes, we need to check if the pattern presents in a file and take some actions depending on the result. ![]()
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