File Processing using AWK & SED | Step by Step Shell Scripts

Explore the cat command's practical uses for file handling: display content with optional line numbers, create and copy files, merge multiple files, and append or reverse content with tac.

Set up and practice with sample data for shell scripting and file processing, downloading four data files from a virtual machine, navigating to downloads, and running commands in the terminal.

Learn to check complete file content using the cat command, view line numbers, skip blank lines, and compare small versus large files for readable output.

Use the head command to view the top of a file; by default it shows 10 lines, or specify lines or bytes, and skip the last 28 lines.

Tail fetches the last portion of a file from the bottom, defaulting to 10 lines. Specify lines with -n or bytes with -c, as shown on the movies file.

Learn to view large files page by page using the more command, navigate with space, and quit with q, while noting its forward-only paging and bottom controls.

Learn how the less command provides paging with forward and backward navigation, unlike more. Open a file with less, move pages, and exit with q.

Master redirection in Unix: save command outputs to files with > and >>, capturing results from grep and head for later use.

Learn to connect commands with the pipe operator, sending the first command’s output as input to the next, using head, tail, grep, and ps -ef to filter results.

learn to use the cmp command to compare two files byte by byte, identify the first differing byte, and explore options to limit the comparison or reveal all changed bytes.

Explore the comm command to compare two sorted files, read its three-column output, and filter results with -1, -2, -3 to show common data or lines exclusive to a file.

Learn to compare two files line by line with diff, using options -q, -s, -y for side-by-side output and suppress common lines to show only differences.

Learn to use the awk command to extract single, multiple, or all columns from a space-separated file, print with or without a separator, and customize column order.

Learn to extract columns from files with awk by specifying separators, using -F or FS, including space, comma, and pipe, to display first, second, and third columns.

Learn to use awk to fetch specific rows and columns, set field separators with -F, and filter data with nr-based conditions, including excluding or including headers.

Learn how to save the output of an awk command to a file using redirection, create the file, and verify its contents for later use in shell scripts.

Learn to use awk to filter data and perform conditional selection. Print specific columns or full rows based on numeric or string conditions, including comparisons and quoted strings.

Master AWK filtering with the logical and operator to enforce multiple field conditions. Print only records where ID exceeds 20 and salary exceeds 500k.

Learn to use awk with the logical or operator to filter records by multiple column conditions and print selected fields from customer data.

Learn to filter data with awk by substring matches, either across an entire row or within a specific column, and compare substring containment to exact value conditions.

Learn to filter process records with awk in shell scripts by matching conditions on uid, root, and pid, using and/or logic to display targeted rows.

Learn how awk finds records starting with the letter e, using the start-of-line anchor and printing the full lines, focusing on column two.

Discover how awk matches text at line ends and in columns, prints full records ending with a given character, and combines start and end conditions.

Learn to filter running processes saved to a file by the last column using awk and sed, matching a substring anywhere or at the start.

Save all processes to a file, pick matching records, and locate the value ten anywhere in a row or column, then update data as part of the process.

Explore conditional checks in awk using if statements to filter records by salary, applying and or logic and using a pipe as the field separator.

Master awk conditional logic with if-else to display names or stars based on salary thresholds, using -F for field separation and print statements.

Learn to perform if-else if-else checks in awk, applying salary thresholds (≥ 30,000; ≥ 20,000; else) to compute taxes (30%, 20%, and 10%), format output, and hide the header.

Identify and replace root with super user in the user column using awk and sed; then display route for records with route and show no user for all others.

Learn how awk begin block initializes variables and prints headers before the action block, then filters records by salary 10,000 and optionally doubles the salary in the action block.

Explore awk begin, action, and end blocks to count records, such as salaries over 10,000, and display results, with end-block tasks like 'task is done' after processing.

Learn how to use a while loop in awk to print each input line twice, with a pipe as the field separator, by declaring a counter and iterating two times.

Learn how to use awk with a for loop to repeat lines, set a field separator, and print lines or specific fields like $0 and $1 to format records.

Store the awk command result into a variable using -F '|' to set the field separator and print $2 for names. Display the stored data by referencing the variable.

Learn how to run awk commands without a file name by using begin and end blocks and action blocks.

Learn how to split a data file by column values with awk, using -F, to create separate files for each job title or office code from employee data.

Split a file by column data using awk, and output target files containing only selected columns such as employee number, last name, and first name.

Learn how to use awk to calculate the length of strings in a csv column, extracting the last name from the second field and printing its length.

Explore awk string functions to convert names to upper and lower case, print specific fields, and apply the two upper and two lower transformations in shell scripts.

Study how to use awk's sub and gsub to replace the first or all occurrences in specific columns, print updated fields, and switch characters to symbols in shell scripts.

Explore awk's index and substring functions to locate a character position and extract a four-character substring from a column.

Explore printf basics for formatting in shell scripts, contrast it with print, and learn to apply data types, such as string and integer, using format specifiers and awk field separators.

Master printf formatting by adding tabs and pipes between two columns (it and string), suppress the header row, and create a pipe-delimited, tab-separated table in the shell.

Explore printf string formatting in awk, defining column width and alignment for string columns. Learn to set width with %s, use hyphen for left alignment, and observe default right alignment.

Explore printf number formatting in shell scripting by defining column width, applying left or right alignment, and padding numbers with leading zeros for numeric columns.

Learn what sed is as a stream editor for file processing. Use line numbers or context to insert, update, delete, and search data with linear browsing or context based operations.

Explore how to use sed to display a specific line and to print a line multiple times by its number, with practical terminal examples on an Ubuntu file.

Learn to display the last line with the dollar sign and print specific line ranges using sed, such as 2-4, and avoid duplicates by using the -n option with p.

Learn to use sed to skip lines in a file, displaying all lines except a specific line or a specified range, using negation and range expressions.

learn to use sed to display lines containing a word, perform case-insensitive matches, and apply context addressing within shell scripts, alongside awk.

Learn how to use sed to search a file for lines containing e (case-insensitive) and save the results to a new file, avoiding terminal output.

Learn how to use sed to substitute data in a file by replacing 10,000 with 15,000 using the s/old/new/ syntax and applying changes to the target file.

learn how to replace multiple data in one sed command using -e and s substitutions to swap 10,000 with 15,000 and 20,000 with 25,000 in a file.

Apply sed to substitute data by matching conditions, such as changing 10,000 to 15,000 only when the name is Johnny, and 20,000 to 25,000 only when the name is AJ.

Learn how to delete lines from a file using sed, performing in-place edits, and handle case-insensitive matches to remove both capital and lowercase instances of Simon.

Learn to insert data into a file with sed, including the -i option for in-place edits. See how to insert on the first line and add subsequent lines.

Explore how to use the cut command to extract specific character positions and ranges from column formatted data. Master -c for first characters and ranges like 1-4 and 5-.

Use the cut command to display specific columns from comma-separated files. Define the delimiter with -d and pick columns with -f, including ranges like 1-3 or 3-end.

Apply the cut command to display selected columns and skip others using -d and -f, with --complement to omit columns, and use ranges like 3-5 plus change the output delimiter.

Learn how to use the cut command to extract the third to fifth columns from a comma-delimited file and skip lines lacking a delimiter.

Learn to search data in a file with grep, the global regular expression parser, using patterns like 2010 or 2008 to highlight matches.

Master searching data across multiple files with grep in the terminal, using hotels and movies as examples to find lines containing john, 190, or 38.

Learn to search data in all files in a directory using grep, using wildcards to match any name and extension, and interpret results across multiple files.

learn to search data in files with case-insensitive matching using grep, applying grep -i to find matches regardless of case across one or multiple files.

Learn to search data in files and display matching line numbers with grep -n, using examples in movies and hotels to locate exact lines like 72 or 26.

Learn to use grep to display only file names with the -l option. Practice ignore-case searches across multiple files to identify where data matches.

Use grep -w to match exact words, not substrings, and learn ignore-case usage, as shown with John versus Johnson and 38 across files.

Learn to search data by excluding given text with grep -v, perform reverse searches, handle case with -i, and display records not containing the specified word across sample files.

Learn to count matches with grep by displaying only the number of occurrences using -c, including case-insensitive searches with -i, and apply it to sample files.

Learn to search data with grip and display surrounding lines by using -B, -A, or -C to show preceding, following, or both around each match, including ignore case options.

Perform extended searches with grep using -e to match any number of terms in one command and display matching lines, optionally with -i for case-insensitive results.

Explore how to search multiple patterns with egrep (extended grep) using -e, -i, and -n options and pipes to retrieve matching lines from data files.

Explore processing a running process in a file and practice filtering lines with grep to display records containing bin and those that do not, as part of shell scripts.

Learn to count occurrences of bin in a file using grep, save results to a log, and obtain line-numbered results to identify where bin appears.

Filter file records with awk and sed to display only the top two results for a search. Emphasize counting and selective display of search results.