What I'm basically trying to do is automatically detect if there is text in a line, and if so create a new variable containing the text in said line , within a script. If there is no text in a line then the variable doesn't get created. I can do this manually by opening the file -
$ cat file.txt
sometxt
somemoretext
evenmoretext
...
then adding to my script the appropriate lines -
TXT=file.txt
VAR1=$(sed -n 1p $TXT)
VAR2=$(sed -n 2p $TXT)
...
but this is a pain since I have to count how many lines there are total, then copy and paste each line assigning the variables and changing 'VAR!' to 'VAR2' and '1p' to '2p'. There has to be an easier way. Thanks
#JNevil thanks for pointing me in the right direction.
Heres what ended up working for me -
for var_name in (cat links.txt); do
wget <servername.com>$var_name
done
Still dont know how to use curl but this worked fine!
Related
I have a text file, called texto.txt in Documentos folder, with some values like the ones below:
cat ~/Documentos/texto.txt
65f8: Testado
a4a1: Testado 2
So I want to change a whole line by using a customized function which gets as parameters the new value.
The new value will always keep the first 6 characters, changing only what comes after them. Although I am testing only the first four.
Then I edited my .bashrc including my function like shown below.
muda()
{
export BUSCA="$(echo $* | cut -c 1-4)";
sed -i "/^$BUSCA/s/.*/$*/" ~/Documentos/texto.txt ;}
When I run the command below it works like a charm, but I feel it could be improved.
muda a4a1: Testado 3
Result:
cat ~/Documentos/texto.txt
65f8: Testado
a4a1: Testado 3
Is there a smarter way to do this? Maybe by getting rid of BUSCA variable?
I'd write:
muda() {
local new_line="$*"
local key=${newline:0:4}
sed -i "s/^${key//\//\\/}.*/${new_line//\//\\/}/" ~/Documentos/texto.txt
}
Notes:
using local variables, not exported environment variables
does not call out to cut, bash can extract a substring
escaping any slashes in the variable values so the sed code is not broken.
I made a shell script the purpose of which is to find files that don't contain a particular string, then display the first line that isn't empty or otherwise useless. My script works well in the console, but for some reason when I try to direct the output to a .txt file, it comes out empty.
Here's my script:
#!/bin/bash
# takes user input.
echo "Input substance:"
read substance
echo "Listing media without $substance:"
cd media
# finds names of files that don't feature the substance given, then puts them inside an array.
searchresult=($(grep -L "$substance" *))
# iterates the array and prints the first line of each - contains both the number and the medium name.
# however, some files start with "Microorganisms" and the actual number and name feature after several empty lines
# the script checks for that occurence - and prints the first line that doesnt match these criteria.
for i in "${searchresult[#]}"
do
grep -m 1 -v "Microorganisms\|^$" $i
done >> output.txt
I've tried moving the >>output.txt to right after the grep line inside the loop, tried switching >> to > and 2>&1, tried using tee. No go.
I'm honestly feeling utterly stuck as to what the issue could be. I'm sure there's something I'm missing, but I'm nowhere near good enough with this to notice. I would very much appreciate any help.
EDIT: Added files to better illustrate what I'm working with. Sample inputs I tried: Glucose, Yeast extract, Agar. Link to files [140kB] - the folder was unzipped beforehand.
The script was given full permissions to execute. I don't think the output is being rewritten because even if I don't iterate and just run a single line of the loop, the file is empty.
I am currently working on a little script for the "nslookup"-command and in my testing I encountered a problem I don't understand. In my script a .txt file is automatically created and the user can input some text to it if he wishes to. He can also delete specific lines in the document. I tried writing it with "sed" but it doesn't seem to be working correctly.
Here the menu from the terminal output:
Domains:
1) new_domain
2) domain
3) Create new Domain
4) Delete a Domain
5) Quit
Input>
The first two numbers also representing the line of each text.
The code for deleting a domain is the following:
filename=domains.txt
old_filename=domains_backup.txt
read -p "Which domain-number shall be deleted?: " num_input
mv $filename $old_filename
sed "/$num_input/d" < $old_filename > $filename
rm $old_filename
But when executing that script and the user wants to delete line 2 (domain) the text-file remains the same and is not updated.
When I try the same only using the terminal everything works fine.
Is there something I'm missing?
To delete a line by its line number you will want to use $num_input d rather than /$num_input/d : the second one matches lines that contain $num_input.
As a side note, if you use GNU sed you could let it handle the backup :
sed -i.backup "$num_input d" domains.txt
This would create a copy of the untouched domains.txt as domains.txt.backup (or whatever suffix you specify after -i) and update the domains.txt file.
Here is an extract from a script showing the variables for the script
PathToPiconPNG="/var/OscamSrvidPicon/picon/19.2E/"
PathToOscamSrvid="/var/OscamSrvidPicon/picon/19.2E/oscam.srvid"
PathToPiconTPL="/var/OscamSrvidPicon/oscam_picons/"
PathToTmp="/tmp/"
I want to run this script numerous times replacing (for example) this line:
PathToPiconPNG="/var/OscamSrvidPicon/picon/19.2E/"
with this lines
PathToPiconPNG="/var/OscamSrvidPicon/picon/28.2E/"
I have tried using sed (I know this example is wrong but you might get what im trying to achieve)
sed 's/{PathToPiconPNG="/var/OscamSrvidPicon/picon/19.2E/"}/{PathToPiconPNG="/var/OscamSrvidPicon/picon/28.2E/"}/g' filename.txt > newfilenam.txt
If that is not possible, is there any way that I can set the variable externally from another script
sed -E 's/picon\/.+\//picon\/28.2E\//' filename.txt > newfilenam.txt
I'm trying to use the rename command in a Terminal in Ubuntu to append a string to the beginning of some avi file names as follows.
rename -n 's/(\w)\.avi$/String_to_add__$1\.avi/' *.avi
So I expect the following:
String_to_add_MyMovie.avi
Problem is that when I run the command it appends the string to the end of the file name, so I end up with the following:
MyMovie_String_to_add_.avi
I'm not sure if I have the perlexpr syntax wrong or something else. Any insight is appreciated.
UPDATE:
Thanks for the suggestions, I tried the suggestions from alno and plundra and made the following modification:
rename -n 's/(\w+)\.avi$/String_to_add__$1\.avi/' *.avi
But now the file gets the string inserted in the middle of the name as follows:
My_String_to_add_Movie
My apologies though, I neglected to mention that the titles are preceded by 3 numeric values, so the file name nomenclature is {3 numbers}-My_Movie.avi so for example 001-My_Movie.avi. But I didn't think this would make a difference since I'm assuming \w+ matches alphanumeric characters, might the '-' be the issue?
Haven't tried Christian's approach yet, I want to be able to use the rename command, or at least understand why it's not working before I try a different approach.
I don't think rename -n is standard. You could do this:
for i in *.avi; do mv $i String_to_add_$i; done
You're only matching a single character with \w, you want \w+, so the complete line would be:
rename -n 's/(\w+)\.avi$/String_to_add__$1\.avi/' *.avi
Correct version:
rename -n 's/(\w+)\.avi$/String_to_add__$1\.avi/' *.avi
You simply forgot + after \w, so it tried to match only one character.