sed [OPTION]... {script-only-if-no-other-script} [input-file]...
Usage: sed [OPTION]... {script-only-if-no-other-script} [input-file]...
-n, --quiet, --silent
suppress automatic printing of pattern space
--debug
annotate program execution
-e script, --expression=script
add the script to the commands to be executed
-f script-file, --file=script-file
add the contents of script-file to the commands to be executed
--follow-symlinks
follow symlinks when processing in place
-i[SUFFIX], --in-place[=SUFFIX]
edit files in place (makes backup if SUFFIX supplied)
-l N, --line-length=N
specify the desired line-wrap length for the `l' command
--posix
disable all GNU extensions.
-E, -r, --regexp-extended
use extended regular expressions in the script
(for portability use POSIX -E).
-s, --separate
consider files as separate rather than as a single,
continuous long stream.
--sandbox
operate in sandbox mode (disable e/r/w commands).
-u, --unbuffered
load minimal amounts of data from the input files and flush
the output buffers more often
-z, --null-data
separate lines by NUL characters
--help display this help and exit
--version output version information and exit
If no -e, --expression, -f, or --file option is given, then the first
non-option argument is taken as the sed script to interpret. All
remaining arguments are names of input files; if no input files are
specified, then the standard input is read.
GNU sed home page: <https://www.gnu.org/software/sed/>.
General help using GNU software: <https://www.gnu.org/gethelp/>.
E-mail bug reports to: <bug-sed@gnu.org>.
Replace string with new string
sed 's/<string-to-replace>/<new-string>' <file>
Replace one occurrence per line
$ cat testfile.txt
This is first line test content for a test file.
This is second line test content for a test file.
$ cat testfile.txt | sed 's/test/real/'
This is first line real content for a test file.
This is second line real content for a test file.
Replace all occurrences per line, add ‘g’, can also be a number of occurrences per line
$ cat testfile.txt
This is first line test content for a test file.
This is second line test content for a test file.
$ cat testfile.txt | sed 's/test/real/g'
This is first line real content for a real file.
This is second line real content for a real file.
find -type f -name "*.md" | xargs sed -i '2d;4,6d;8,10d;12d;14,26d;28d;30,31d;33,34d'