{"id":93,"date":"2024-12-16T08:02:48","date_gmt":"2024-12-16T08:02:48","guid":{"rendered":"https:\/\/techkubo.com\/linux\/?p=93"},"modified":"2025-05-28T17:55:33","modified_gmt":"2025-05-28T17:55:33","slug":"linux-sed-command","status":"publish","type":"post","link":"https:\/\/techkubo.com\/linux\/linux-sed-command\/","title":{"rendered":"Linux – sed Command"},"content":{"rendered":"\n

The sed<\/code> command stands for “stream editor.” It is used to perform basic text transformations on an input stream. The sed<\/code> command is commonly used for text substitution, filtering, and other text processing tasks.<\/p>\n\n\n\n

Initial Example<\/h2>\n\n\n\n

Using sed<\/code> to replace the first occurrence of the word “old” with “new” in a file called file.txt<\/code>:<\/p>\n\n\n\n

sed 's\/old\/new\/' file.txt<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\n
SED Command<\/h2>\n\n\n\n
Parameter<\/th>Description<\/th><\/tr><\/thead>
-n, --quiet, --silent<\/code><\/td>Suppress automatic output printing, only print lines explicitly specified<\/td><\/tr>
--debug<\/code><\/td>Output detailed execution steps for debugging purposes<\/td><\/tr>
-e script, --expression=script<\/code><\/td>Add the provided script to the list of commands to be executed<\/td><\/tr>
-f script-file, --file=script-file<\/code><\/td>Execute commands from the specified script file<\/td><\/tr>
--follow-symlinks<\/code><\/td>Follow symbolic links when making in-place edits<\/td><\/tr>
-i[SUFFIX], --in-place[=SUFFIX]<\/code><\/td>Edit files directly, optionally making a backup with the given suffix<\/td><\/tr>
-l N, --line-length=N<\/code><\/td>Set the maximum line length for the l<\/code> command, wrapping lines as needed<\/td><\/tr>
--posix<\/code><\/td>Disable all GNU-specific extensions<\/td><\/tr>
-E, -r, --regexp-extended<\/code><\/td>Use extended regular expressions for pattern matching (POSIX -E for portability)<\/td><\/tr>
-s, --separate<\/code><\/td>Treat each file as a separate input stream, rather than a single continuous stream<\/td><\/tr>
--sandbox<\/code><\/td>Run in sandbox mode, disabling the e<\/code>, r<\/code>, and w<\/code> commands for security<\/td><\/tr>
-u, --unbuffered<\/code><\/td>Minimize input buffering and flush output buffers more frequently<\/td><\/tr>
-z, --null-data<\/code><\/td>Use NUL characters to separate lines of input instead of newline characters<\/td><\/tr>
--help<\/code><\/td>Show help information and exit<\/td><\/tr>
--version<\/code><\/td>Display version information and exit<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Examples<\/h2>\n\n\n\n
1. Basic Text Substitution<\/h4>\n\n\n\n
To replace the first occurrence of “old” with “new” in each line of a file:<\/p>\n\n\n\n
sed 's\/old\/new\/' filename.txt<\/pre><\/div>\n\n\n\n
2. Global Text Substitution<\/h4>\n\n\n\n
To replace all occurrences of “old” with “new” in each line of a file:<\/p>\n\n\n\n
sed 's\/old\/new\/g' filename.txt<\/pre><\/div>\n\n\n\n
3. In-Place Editing<\/h4>\n\n\n\n
To perform text substitution directly in the file (without creating a new file):<\/p>\n\n\n\n
sed -i 's\/old\/new\/g' filename.txt<\/pre><\/div>\n\n\n\n
4. Deleting Lines<\/h4>\n\n\n\n
To delete lines that match a specific pattern:<\/p>\n\n\n\n
sed '\/pattern\/d' filename.txt<\/pre><\/div>\n\n\n\n
5. Printing Specific Lines<\/h4>\n\n\n\n
To print only the lines that match a specific pattern:<\/p>\n\n\n\n
sed -n '\/pattern\/p' filename.txt<\/pre><\/div>\n\n\n\n
6. Replace on a Specific Line<\/h4>\n\n\n\n
To replace text on a specific line number (e.g., line 3):<\/p>\n\n\n\n
sed '3s\/old\/new\/' filename.txt<\/pre><\/div>\n\n\n\n
7. Using Regular Expressions<\/h4>\n\n\n\n
To use regular expressions for more complex text manipulation:<\/p>\n\n\n\n
sed 's\/[0-9]\/#\/g' filename.txt<\/pre><\/div>\n\n\n\n
8. Append Text After a Match<\/h4>\n\n\n\n
To append text after lines that match a specific pattern:<\/p>\n\n\n\n
sed '\/pattern\/a\\new text' filename.txt<\/pre><\/div>\n\n\n\n
9. Insert Text Before a Match<\/h4>\n\n\n\n
To insert text before lines that match a specific pattern:<\/p>\n\n\n\n
sed '\/pattern\/i\\new text' filename.txt<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\n
Linux Playground<\/h2>\n\n\n\n