I have a simple .csv file with lines that holds 't' values. Here is the example:
2ABC;t;t;t;tortuga;fault;t;t;bored
I want to replace them to '1' using sed.
If I make sed "s/;t;/;1;/g" I get the next result:
2ABC;1;t;1;tortuga;fault;1;t;bored
As you can see, consecutive ';t;' have been replaced through one. Yes, I can replace all ';t;' by sed -e "s/;t;/;1;/g" -e "s/;t;/;1;/g" but this is boring.
How can I make the replacement by one sed command?
If there is something to replace, branch to replace again.
sed ': again; /;t;/{ s//;1;/; b again }'
Overall, parsing cvs with sed is crude. Consider awk.
awk -F';' -v OFS=';' '{ for(i=1;i<=NF;++i) if ($i=="t") $i=1 } 1'
Lookarounds is helpful in such cases:
$ s='t;2ABC;t;t;t;tortuga;fault;t;t;bored;t'
$ echo "$s" | perl -lpe 's/(?<![^;])t(?![^;])/1/g'
1;2ABC;1;1;1;tortuga;fault;1;1;bored;1
echo '2ABC;t;t;t;tortuga;fault;t;t;bored' |
— gawk-specific solution
gawk -be '(ORS = RT)^!(NF = NF)' FS='^t$' OFS=1 RS=';'
— cross-awk-solution
{m,g,n}awk 'gsub(FS, OFS, $!(NF = NF))^_' FS=';t;' OFS=';1;' RS=
2ABC;1;1;1;tortuga;fault;1;1;bored
I have a file with the following content.
test1
test2
test3
test4
test5
If I want to concatenate all lines into one line separated by commas, I can use vi and run the following command:
:%s/\n/,/g
I then get this, which is what I want
test1,test2,test3,test4,test5,
I'm trying to use sed to do the same thing but I'm missing some unknown command/option to make it work. When I look at the file in vi and search for "\n" or "$", it finds the newline or end of line. However, when I tell sed to look for a newline, it pretends it didn't find one.
$ cat test | sed --expression='s/\n/,/g'
test1
test2
test3
test4
test5
$
If I tell sed to look for end of line, it finds it and inserts the comma but it doesn't concatenate everything into one line.
$ cat test | sed --expression='s/$/,/g'
test1,
test2,
test3,
test4,
test5,
$
What command/option do I use with sed to make it concatenate everything into one line and replace the end of line/newline with a comma?
sed reads one line at a time, so, unless you're doing tricky things, there's never a newline to replace.
Here's the trickiness:
$ sed -n '1{h; n}; H; ${g; s/\n/,/gp}' test.file
test1,test2,test3,test4,test5
h, H, g documented at https://www.gnu.org/software/sed/manual/html_node/Other-Commands.html
When using a non-GNU sed, as found on MacOS, semi-colons before the closing braces are needed.
However, paste is really the tool for this job
$ paste -s -d, test.file
test1,test2,test3,test4,test5
If you really want the trailing comma:
printf '%s,\n' "$(paste -sd, file)"
tr instead of sed for this one:
$ tr '\n' ',' < input.txt
test1,test2,test3,test4,test5,
Just straight up translate newlines to commas.
Based on how can i replace each newline n with a space using sed:
sed -e ':a' -e 'N' -e '$!ba' -e 's/\n/,/g' <file>
testing:
$ cat file.txt
test1
test2
test3
test4
test5
$ sed -e ':a' -e 'N' -e '$!ba' -e 's/\n/,/g' file.txt
test1,test2,test3,test4,test5
Of course, if the question would have been more generic: How do I replace \n with any character using sed then one should only replace the , with ones desired char:
export CHAR_TO_REPLACE=','
export FILE_TO_PROCESS=<filename>
sed -e ':a' -e 'N' -e '$!ba' -e "s/\n/${CHAR_TO_REPLACE}/g" $FILE_TO_PROCESS
This answer is to satisfy the requirement of using sed. Otherwise, you can use alternatives like tr, awk etc.
This might work for you (GNU sed):
sed 'H;1h;$!d;x;y/\n/,/' file
Append all lines but the first to the hold space (the first replaces the hold space).
If it is not the last line of the file, delete it.
Otherwise, swap to the hold space and translate all newlines to commas.
I'm looking for an equivalent of perl -pe. Ideally, it would be replace with sed if it's possible. Any help is highly appreciated.
The code is:
perl -pe 's/^\[([^\]]+)\].*$/$1/g'
$ echo '[foo] 123' | perl -pe 's/^\[([^\]]+)\].*$/$1/g'
foo
$ echo '[foo] 123' | sed -E 's/^\[([^]]+)\].*$/\1/'
foo
sed by default accepts code from command line, so -e isn't needed (though it can be used)
printing the pattern space is default, so -p isn't needed and sed -n is similar to perl -n
-E is used here to be as close as possible to Perl regex. sed supports BRE and ERE (not as feature rich as Perl) and even that differs from implementation to implementation.
with BRE, the command for this example would be: sed 's/^\[\([^]]*\)\].*$/\1/'
\ isn't special inside character class unless it is an escape sequence like \t, \x27 etc
backreferences use \N format (and limited to maximum 9)
Also note that g flag isn't needed in either case, as you are using line anchors
On a Unix system I am trying to add a new line in a file using sed or perl but it seems I am missing something.
Supposing my file has multiple lines of texts, always ending like this {TNG:}}${1:F01.
I am trying to find a to way to add a new line after the }$, in this way {1 should always start on a new line.
I tried it by escaping $ sign using this:
perl -e '$/ = "\${"; while (<>) { s/\$}\{$/}\n{/; print; }' but it does not work.
Any ideas will be appreciated.
give this a try:
sed 's/{TNG:}}\$/&\n/' file > newfile
The sed will by default use BRE, that is, the {}s are literal characters. But we must escape the $.
kent$ cat f
{TNG:}}${1:F01.
kent$ sed 's/{TNG:}}\$/&\n/' f
{TNG:}}$
{1:F01.
With perl:
$ cat input.txt
line 1 {TNG:}}${1:F01
line 2 {TNG:}}${1:F01
$ perl -pe 's/TNG:\}\}\$\K/\n/' input.txt
line 1 {TNG:}}$
{1:F01
line 2 {TNG:}}$
{1:F01
(Read up on the -p and -n options in perlrun and use them instead of trying to do what they do in a one-liner yourself)
I have the followiing input file and I need to remove all the characters from the strings that appear after the last '/'. I'll also show my expected output below.
input:
/start/one/two/stopone.js
/start/one/two/three/stoptwo.js
/start/one/stopxyz.js
expected output:
/start/one/two/
/start/one/two/three/
/start/one/
I have tried to use sed but with no luck so far.
You could simply use good old grep:
grep -o '.*/' file.txt
This simple expression takes advantage of the fact that grep is matching greedy. Meaning it will consume as much characters as possible, including /, until the last / in path.
Original Answer:
You can use dirname:
while read line ; do
echo dirname "$line"
done < file.txt
or sed:
sed 's~\(.*/\).*~\1~' file.txt
perl -lne 'print $1 if(/(.*)\//)' your_file
Try this GNU sed command,
$ sed -r 's~^(.*\/).*$~\1~g' file
/start/one/two/
/start/one/two/three/
/start/one/
Through awk,
awk -F/ '{sub(/.*/,"",$NF); print}' OFS="/" file