I need to edit a text file by adding a blank line above every line starting with a period.
Before
Corn
.Apple
Words.
.Orange
Bean
After
Corn
.Apple
Words.
.Orange
Bean
Here is what I have so far.
This adds a spaces after every period. There are more in the actual file.
cat File.txt | sed -r 's/([.]+)/\n\1/g'
This displays the lines that start with a period
while read -r line; do
if [[ "$line" == "."* ]]; then
echo "$line"
fi
done < File.txt
How do I merge them together?
This produces the output that you want:
$ sed 's/^[.]/\n./' file
Corn
.Apple
Words.
.Orange
Bean
If you want to change the file in-place, use sed's -i option:
sed -i 's/^[.]/\n./' file
For Mac OSX or other BSD system, use:
sed -i '' 's/^[.]/\n./' file
We use ^ which matches only at the beginning of a line. Since we are matching a period at the beginning of the line, it is not necessary to capture a group with parentheses: we know the match is a period. All that we need to do is add a newline before that period.
with sed
sed 's/^\./\n\./'
with awk
awk '/^\./{print ""} 1'
or
awk 'sub(/^\./,"\n.") 1'
Using RegExp it could be:
cat File.txt | sed -r 's/^(\..+)/\n\1/g'
I think an awk script is going to work best.
/^\./ {print "";}
{print $0;}
Put that into a file, in this case, called "awkfile" and run it like `awk -f awkfile File.txt'
$ sed -e '/^\./i\\' pru.txt
Corn
.Apple
Words.
.Orange
Bean
this command line instructs sed(1) to search for lines beginning with a dot, and then insert a blank line before it. Look in sed(1) manual page for how to use the insert, replace and append commands.
Related
I'm trying to change a specific given letter to uppercase in a file, but I don't know how to do it. The file already exist and I want to do the following
cat merry.txt
I wish you a Merry Christmas
Change e to E so the output will be
cat merry.txt
I wish you a MErry Christmas
Thank you everyone
Try this :
sed 's/e/E/' merry.txt
If your text included more than one occurrence of ”e” on a line, the preceding sed would
have changed just the first occurrence on each line to ”E.” By appending the global option
g to the end of the s command, you can ensure that multiple occurrences of the string on a line will be changed.
Try to use this :
sed 's/e/E/g' merry.txt
This command converts all e to E.
Or can use :
sed -i 's/e/E/g' merry.txt
Like this:
sed 's/e/\Ue/' Input_File
To edit permanently, add -i switch:
sed -i ...
You can use tr to "translate" a char to another char:
tr 'e' 'E' < file > newfile && mv newfile file
You can also use awk (here, a dynamic approach is used):
find='e'
replace='E'
awk -v f="$find" -v r="$replace" '{gsub(f, r)}1' file > newfile && mv newfile file
With GNU sed, you may use
sed -i 'y/e/E/' file
In all these case, you replace an e with E everywhere in the file and save the contents of the updated file under the same filename.
See a sample demo online:
#!/bin/bash
s='I wish them a Merry Christmas'
find='e'
replace='E'
tr "$find" "$replace" <<< "$s"
awk -v f="$find" -v r="$replace" '{gsub(f, r)}1' <<< "$s"
sed 'y/e/E/' <<< "$s"
Output: I wish thEm a MErry Christmas.
I am trying to replace string into number from the file
So, I have variable &FLOW which need to change to 001, ex :
cat file.txt
This is file ' PISP &FLOW'
PISD.DATA.CYCLE&FLOW..ONE
desired output
This is file ' PISP 001'
PISD.DATA.CYCLE001.ONE
I tried below commands in a script :
for item in file.txt
do
sed 's/\&FLOW/\./001/g' $item
sed 's/\&FLOW/001/g' $item
done
It is giving error. The second sed command is working, but I need to run first the beginning sed command otherwise after running first the second sed command, it would ignore the beginning sed command.
Any help would be appreciated!
Use a single sed command and use -i to actually modify the file contents and you need to pass file.txt as the input for the sed command:
sed -i 's/&FLOW\.\{0,1\}/001/g' file.txt
See the online demo. If you are using it in Mac OS, you need sed -i '' 's/&FLOW\.\{0,1\}/001/g' file.txt. Also see sed edit file in place.
Pattern details
It is a POSIX BRE compliant pattern matching
&FLOW - a literal &FLOW substring
\.\{0,1\} - 0 or 1 occurrence of a . char.
try this:
for item in file.txt
do
sed 's/\&FLOW\./001/g' $item
sed 's/\&FLOW/001/g' $item
done
You had a redundant / in after FLOW
This might also work:
sed -i 's/\&FLOW[\.]?/001/g' file.txt
I am attempting to use sed to delete a line, read from user input, from a file whose name is stored in a variable. Right now all sed does is print the line and nothing else.
This is a code snippet of the command I am using:
FILE="/home/devosion/scripts/files/todo.db"
read DELETELINE
sed -e "$DELETELINE"'d' "$FILE"
Is there something I am missing here?
Edit: Switching out the -e option with -i fixed my woes!
You need to delimit the search.
#!/bin/bash
read -r Line
sed "/$Line/d" file
Will delete any line containing the typed input.
Bear in mind that sed matches on regex though and any special characters will be seen as such.
For example searching for 1* will actually delete lines containing any number of 1's not an actual 1 and a star.
Also bear in mind that when the variable expands, it cannot contain the delimiters or the command will break or have unexpexted results.
For example if "$Line" contained "/hello" then the sed command will fail with
sed: -e expression #1, char 4: extra characters after command.
You can either escape the / in this case or use different delimiters.
Personally i would use awk for this
awk -vLine="$Line" '!index($0,Line)' file
Which searches for an exact string and has none of the drawbacks of the sed command.
You might have success with grep instead of sed
read -p "Enter a regex to remove lines: " filter
grep -v "$filter" "$file"
Storing in-place is a little more work:
tmp=$(mktemp)
grep -v "$filter" "$file" > "$tmp" && mv "$tmp" "$file"
or, with sponge (apt install moreutils)
grep -v "$filter" "$file" | sponge "$file"
Note: try to get out of the habit of using ALLCAPSVARS: one day you'll accidentally use PATH=... and then wonder why your script is broken.
I found this, it allows for a range deletion with variables:
#!/bin/bash
lastline=$(whatever you need to do to find the last line)` //or any variation
lines="1,$lastline"
sed -i "$lines"'d' yourfile
keeps it all one util.
Please try this :
sed -i "${DELETELINE}d" $FILE
Say for instance I'm searching a line that is like this:
Color asdf
and I use grep to find that line, like grep asdf file.txt
How would I then display Color? Learning linux is hard.
With the command line tool sed you can replace stings by using regular expressions:
echo "Color asdf" | sed 's/\([^ ]*\).*/\1/'
This part: \([^ ]*\).* is a regular expresion. The first part of the regex: [^ ]*, matches any character except a space as many times as possible and what's between the \( and \) is being captured in the variable \1. Then you also match the remaining part of the string with .* and replace all of that with only the first word which was captured by \([^ ]*\) by using \1 in the replace part of the sed command.
Here some more info about sed:
http://linux.about.com/od/commands/a/Example-Uses-Of-Sed-Cmdsedxa.htm
You could use sed:
sed -n 's/[[:space:]][[:space:]]*asdf$//p' file.txt
Details:
The -n option tells sed not to print the pattern space automatically. Basically, it doesn't output anything unless you tell it to.
The s command of sed replaces text. Here, if a line ends with asdf, preceded by at least one whitespace character, we replace all of that with nothing and then print the line (notice the p flag at the end of the s command). The printing is only done if something was actually replaced. More information about the s command can be found e. g. in the GNU sed manual.
Edit for clarity: When using single quotes, parameter expansion does not work and thus, variables won't be replaced. To use variables, use double quotes:
search=asdf
sed -n "s/[[:space:]][[:space:]]*${search}\$//p" file.txt
If you'd really like to use grep here, you could pipe the output from grep into cut:
grep -h asdf *.txt | cut -s -d -f 1
Note that there have to be two spaces after the -d option to cut - the first tells cut to use a blank as the field delimiter (I'm assuming your fields are blank-delimited rather than tab-delimited), while the second separates the -d option from the following option (-f).
But, yeah, sed or awk are probably your friends here... :-)
you can color pattern in the line using grep
grep --colour -o 'asdf' file.txt
edit: the -o option will print only the patterns
I am reading files and i am doing something like:
cat file | sed s/\ //g |awk '$0 !~ /[^0-9]/'
With this line I want to clean anything different to numbers.
But i have a problem, when the file is not sorted the command works fine, but with a sorted file the command not works, the output is empty.
Who can help me?
with grep -o '[0-9]+' not works because:
I have a file like:
311435ll3e
kk13322;.
erre433
The output is:
311435
3
13322
433
And the 3 is in the second line, the output that i need is:
3114353
13322
433
As a general rule, there is no reason to have both awk and sed appearing in the same pipe, due to a large overlap of capability, and frequently the same is true of awk/grep/sed combinations.
If you just want to suppress the non-digit characters within lines of characters, use (eg) sed -e 's/[^0-9]//g' file, or if you want to do it in place with no backup, sed -i -e 's/[^0-9]//g' file, or in place with backup to a .bak file, sed -ibak -e 's/[^0-9]//g' file.
To suppress blank lines, you can append |egrep -v '^$' after the sed, but it's more efficient to just use sed's d command to delete the pattern space and start next cycle if the pattern space is empty. For example,
sed -e 's/[^0-9]//g; /^$/d' file
does a d if the line is empty after substitution.
The form suggested in 1_CR's comment,
sed -e 's/[^0-9]//g' -e '/./!d'
is an alternative. That form tests if the line has at least one character in it, and if so does not do a d.
If you want to suppress everything in the file that's not digits, use tr -cd 0-9 < file. This suppresses line feeds also.
Note, the form tr -cd [0-9] < file or tr -cd '[0-9]' < file is not correct; it will fail to suppress ] and [ characters because tr will regard them as part of SET1.