How to add to the end of lines containing a pattern with sed or awk?

Question

Here is example file:

somestuff...
all: thing otherthing
some other stuff

What I want to do is to add to the line that starts with all: like this:

somestuff...
all: thing otherthing anotherthing
some other stuff

score 187 · Accepted Answer · answered Mar 06 '12 at 21:00

187

This works for me

sed '/^all:/ s/$/ anotherthing/' file

The first part is a pattern to find and the second part is an ordinary sed's substitution using $ for the end of a line.

If you want to change the file during the process, use -i option

sed -i '/^all:/ s/$/ anotherthing/' file

Or you can redirect it to another file

sed '/^all:/ s/$/ anotherthing/' file > output

answered Mar 06 '12 at 21:00

user219882

Just adding something leads to a new line, replace is the right way. – zhy Nov 02 '18 at 08:34
2

On Mac OSX, for the `-i` option, I had to do like: `sed -i '' -e '/^all:/ s/$/ anotherthing/' file` – Mahdi Feb 03 '21 at 14:09

score 19 · Answer 2 · answered Jan 25 '15 at 16:47

You can append the text to $0 in awk if it matches the condition:

awk '/^all:/ {$0=$0" anotherthing"} 1' file

/patt/ {...} if the line matches the pattern given by patt, then perform the actions described within {}.
In this case: /^all:/ {$0=$0" anotherthing"} if the line starts (represented by ^) with all:, then append anotherthing to the line.
1 as a true condition, triggers the default action of awk: print the current line (print $0). This will happen always, so it will either print the original line or the modified one.

For your given input it returns:

somestuff...
all: thing otherthing anotherthing
some other stuff

Note you could also provide the text to append in a variable:

$ awk -v mytext=" EXTRA TEXT" '/^all:/ {$0=$0mytext} 1' file
somestuff...
all: thing otherthing EXTRA TEXT
some other stuff

@ceving then you can use `/usr/xpg4/bin/awk` which is the "good" awk. — fedorqui, Feb 19 '16 at 11:16

score 10 · Answer 3 · answered Mar 06 '12 at 21:00

10

This should work for you

sed -e 's_^all: .*_& anotherthing_'

Using s command (substitute) you can search for a line which satisfies a regular expression. In the command above, & stands for the matched string.

answered Mar 06 '12 at 21:00

izidor

sed: -e expression #1, char 21: unknown option to `s' – Mehdi Mar 16 '21 at 16:04

score 9 · Answer 4 · answered Jun 04 '18 at 20:50

Here is another simple solution using sed.

$ sed -i 's/all.*/& anotherthing/g' filename.txt

Explanation:

all.* means all lines started with 'all'.

& represent the match (ie the complete line that starts with 'all')

then sed replace the former with the later and appends the ' anotherthing' word

score 6 · Answer 5 · answered Mar 06 '12 at 21:11

6

In bash:

while read -r line ; do
    [[ $line == all:* ]] && line+=" anotherthing"
    echo "$line"
done < filename

answered Mar 06 '12 at 21:11

glenn jackman

score 5 · Answer 6 · answered Mar 06 '12 at 21:11

5

Solution with awk:

awk '{if ($1 ~ /^all/) print $0, "anotherthing"; else print $0}' file

Simply: if the row starts with all print the row plus "anotherthing", else print just the row.

answered Mar 06 '12 at 21:11

Manlio

4

You can shorten that to: `awk '$1=="all:" {$(NF+1)="anotherthing"} 1'` – glenn jackman Mar 06 '12 at 21:12
2

@Prometheus, an awk script is composed of `condition {actions}` pairs. If the `condition` is omitted, the actions are performed for every record. If the `{actions}` are omitted, and the condition evaluates to *true* (which is the case for the number `1`) then the default action is to print the current record. – glenn jackman Mar 27 '13 at 00:35

6 Answers6