sed(1) — Linux man page
Sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipeline). While in some ways similar to an editor which permits scripted edits (such as ed), sed works by making only one pass over the input(s), and is consequently more efficient. But it is sed‘s ability to filter text in a pipeline which particularly distinguishes it from other types of editors. -n, —quiet, —silent suppress automatic printing of pattern space -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; hard links will still be broken. -i[SUFFIX], —in-place[=SUFFIX] edit files in place (makes backup if extension supplied). The default operation mode is to break symbolic and hard links. This can be changed with —follow-symlinks and —copy. -c, —copy use copy instead of rename when shuffling files in -i mode. While this will avoid breaking links (symbolic or hard), the resulting editing operation is not atomic. This is rarely the desired mode; —follow-symlinks is usually enough, and it is both faster and more secure. -l N, —line-length=N specify the desired line-wrap length for the ‘l’ command —posix disable all GNU extensions. -r, —regexp-extended use extended regular expressions in the script. -s, —separate consider files as separate rather than as a single continuous long stream. -u, —unbuffered load minimal amounts of data from the input files and flush the output buffers more often —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: . General help using GNU software: . E-mail bug reports to: . Be sure to include the word »sed» somewhere in the »Subject:» field.
Command Synopsis
This is just a brief synopsis of sed commands to serve as a reminder to those who already know sed; other documentation (such as the texinfo document) must be consulted for fuller descriptions.
Zero-address »commands» : label Label for b and t commands. #comment The comment extends until the next newline (or the end of a -e script fragment). >
The closing bracket of a < >block.
Zero- or One- address commands =
Print the current line number.
Append text, which has each embedded newline preceded by a backslash.
Insert text, which has each embedded newline preceded by a backslash. q [exit-code] Immediately quit the sed script without processing any more input, except that if auto-print is not disabled the current pattern space will be printed. The exit code argument is a GNU extension. Q [exit-code] Immediately quit the sed script without processing any more input. This is a GNU extension. r filename Append text read from filename. R filename Append a line read from filename. Each invocation of the command reads a line from the file. This is a GNU extension.
Commands which accept address ranges
Begin a block of commands (end with a >). b label Branch to label; if label is omitted, branch to end of script. t label If a s/// has done a successful substitution since the last input line was read and since the last t or T command, then branch to label; if label is omitted, branch to end of script. T label If no s/// has done a successful substitution since the last input line was read and since the last t or T command, then branch to label; if label is omitted, branch to end of script. This is a GNU extension. c \
Replace the selected lines with text, which has each embedded newline preceded by a backslash.
Delete pattern space. Start next cycle.
Delete up to the first embedded newline in the pattern space. Start next cycle, but skip reading from the input if there is still data in the pattern space.
Copy/append pattern space to hold space.
Copy/append hold space to pattern space.
Exchange the contents of the hold and pattern spaces.
List out the current line in a »visually unambiguous» form. l width List out the current line in a »visually unambiguous» form, breaking it at width characters. This is a GNU extension. n N
Read/append the next line of input into the pattern space.
Print the current pattern space.
Print up to the first embedded newline of the current pattern space. s/regexp/replacement/ Attempt to match regexp against the pattern space. If successful, replace that portion matched with replacement. The replacement may contain the special character & to refer to that portion of the pattern space which matched, and the special escapes \1 through \9 to refer to the corresponding matching sub-expressions in the regexp. w filename Write the current pattern space to filename. W filename Write the first line of the current pattern space to filename. This is a GNU extension. y/source/dest/ Transliterate the characters in the pattern space which appear in source to the corresponding character in dest.
Addresses
Sed commands can be given with no addresses, in which case the command will be executed for all input lines; with one address, in which case the command will only be executed for input lines which match that address; or with two addresses, in which case the command will be executed for all input lines which match the inclusive range of lines starting from the first address and continuing to the second address. Three things to note about address ranges: the syntax is addr1,addr2 (i.e., the addresses are separated by a comma); the line which addr1 matched will always be accepted, even if addr2 selects an earlier line; and if addr2 is a regexp, it will not be tested against the line that addr1 matched.
After the address (or address-range), and before the command, a ! may be inserted, which specifies that the command shall only be executed if the address (or address-range) does not match.
The following address types are supported: number
Match only the specified line number. first~step Match every step‘th line starting with line first. For example, »sed -n 1~2p» will print all the odd-numbered lines in the input stream, and the address 2~5 will match every fifth line, starting with the second. first can be zero; in this case, sed operates as if it were equal to step. (This is an extension.) $
Match the last line. /regexp/ Match lines matching the regular expression regexp. \cregexpc Match lines matching the regular expression regexp. The c may be any character. GNU sed also supports some special 2-address forms: 0,addr2 Start out in «matched first address» state, until addr2 is found. This is similar to 1,addr2, except that if addr2 matches the very first line of input the 0,addr2 form will be at the end of its range, whereas the 1,addr2 form will still be at the beginning of its range. This works only when addr2 is a regular expression. addr1,+N Will match addr1 and the N lines following addr1. addr1,~N Will match addr1 and the lines following addr1 until the next line whose input line number is a multiple of N.
Regular Expressions
POSIX.2 BREs should be supported, but they aren’t completely because of performance problems. The \n sequence in a regular expression matches the newline character, and similarly for \a, \t, and other sequences.
Bugs
E-mail bug reports to bonzini@gnu.org. Be sure to include the word »sed» somewhere in the »Subject:» field. Also, please include the output of »sed —version» in the body of your report if at all possible.
Copyright
Copyright © 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, to the extent permitted by law.
GNU sed home page: . General help using GNU software: . E-mail bug reports to: . Be sure to include the word »sed» somewhere in the »Subject:» field.
See Also
The full documentation for sed is maintained as a Texinfo manual. If the info and sed programs are properly installed at your site, the command info sed should give you access to the complete manual.
How to add line numbers in every line using shell command?
You may want to tune w idth option according to the total number of lines in the file (if you want numbers to be aligned nicely).
1> PSS-A (Primary A) 2> PSS-B (Primary B) 3> PSS-C (Primary C) 4> PSS-D (Primary D) 5> PSS-E (Primary E) 6> PSS-F (Primary F) 7> PSS-G (Primary G) 8> PSS-H (Primary H) 9> PSS-I (Primary I) 10> SPARE (SPARE) nl treats lines that contain a sequence of 1, 2 or 3 \: strings specially. Use -d $’\n’ to avoid that. Also, by default, it doesn’t number empty lines. Use -ba to number every line.
@myrdd, $’. ‘ comes from ksh93 and is also supported by zsh , mksh , busybox sh, FreeBSD sh and bash at least. It’s not standard yet, but is planned for inclusion in the next major POSIX version.
@StéphaneChazelas thanks. for reference, there’s a question on $’. ‘ (ANSI-C Quoting) portability: unix.stackexchange.com/questions/371827/…
If you want the same format that you have specified
awk ' " $s>' inputfile > outputfile otherwise, though not standard, most implementations of the cat command can print line numbers for you (numbers padded to width 6 and followed by TAB in at least the GNU, busybox, Solaris and FreeBSD implementations).
cat -n inputfile > outputfile Or you can use grep -n (numbers followed by : ) with a regexp like ^ that matches any line:
grep -n '^' inputfile > outputfile Yes. both the commands are working. but in cat command its printing the line numbers. but not exactly what I wanted. but awk ‘
In Linux/Unix, there are almost always multiple ways to do common tasks. Just for completeness, here are some other ways you can do it besides the obvious:
From an old command to format text to send to a line printer. The ‘-t’ will omit header and footer information that are not relevant to a terminal.
Here’s a cute sed method that prints the line number on every other line. We use ‘paste’ to fold them into a single line:
Or, we can use the one true editor, ed:
Or, ex, vi’s non-cursor-addressing predecessor:
printf 'set number\ng/^/p\n' | ex /etc/passwd And one final complicated answer, requiring ksh93 or bash (and the seq command. Using the .. range and an eval statement is left as an exercise):
Tested on Debian Linux, FreeBSD, and Solaris 10 (the last fails there because of no ‘seq’).
Pattern Search between specific lines and print line numbers
I have a file of 20 lines. I want to search for a string between the lines 10 and 15 and print the string along with the line numbers of the original file. I have tried sed -n 10,15p file | grep -n «pattern» The problem with the above command is, the output line number 10 of sed will be line number 1 for grep . Hence it is not printing the line numbers from the original file.
3 Answers 3
When working w/ sed I typically find it easiest to consistently narrow my possible outcome. This is why I sometimes lean on the ! negation operator. It is very often more simple to prune uninteresting input away than it is to pointedly select the interesting kind — at least, this is my opinion on the matter.
I find this method more inline with sed ‘s default behavior — which is to auto-print pattern-space at script’s end. For simple things such as this it can also more easily result in a robust script — a script that does not depend on certain implementations’ syntax extensions in order to operate (as is commonly seen with sed ).
This is why I recommended you do:
. which first prunes any line not within the range of lines 10 & 15, and from among those that remain prunes any line which does not match pattern . If you find you’d rather have the line number sed prints on the same line as its matched line, I would probably look to paste in that case. Maybe.
. which will just alternate replacing input \n ewlines with either a : character or another \n ewline.
seq 150 | sed '10,50!d;/5/!d;=' | paste -sd:\\n -