I need to use sed in shell to do the following things in a file:
1) Suppose I have a line:
#listen_tcp = 1
I want to delete first character #
2) Suppose I have a line:
#listen_tcp = 1
I want to change to last character 1 to 0
3) Suppose I have a line:
#listen_tcp
I want to append it, to #listen_tcp = 1
4) Suppose I have a line:
libvirtd_opts="-d"
I want to insert something, to libvirtd_opts="-d -l"
5) Suppose I have a line:
tcp_port = "16059"
I just want to change it, to tcp_port = "16509"
How can I use sed to do all of them in a text file? I only know how to relace it with a whole line. For example, I will open the file and remember the line of the words, then use sed s/a/b/g to replace a with b. That's my best knowledge, I wonder if there is better way to achieve this? For instance, search the line by keywords and replace part of this line?
For 1)
echo "#listen_tcp = 1" | sed '/listen/s/#//g'
listen_tcp = 1
For 2)
echo "#listen_tcp = 1" | sed '/listen/s/1/0/g'
#listen_tcp = 0
For 3)
echo "#listen_tcp" | sed 's/#listen_tcp/& = 1/g'
#listen_tcp = 1
For 4)
echo 'libvirtd_opts="-d"' | sed 's/libvirtd_opts="-d/& -l/g'
libvirtd_opts="-d -l"
For 5)
echo 'tcp_port = "16059"' | sed '/tcp_port/s/16059/16509/g'
tcp_port = "16509"
Related
I have a reference file with device names in them. For example WABEL8499IPM101. I'm using this script to set the base name (without the last 3 digits) to look at the reference file and see what is already used. If 101 is used it will create a file for me with 102, 103 if I request 2 total. I'm looking to use an input file to run it multiple times. I'm also trying to figure out how to start at 101 if there isn't a name found when searching the reference file
I would like to loop this using an input file instead of manually entering bash test.sh WABEL8499IPM 2 each time. I would like to be able to build an input file of all the names that need compared and then output. It would also be nice that if there isn't a match that it starts creating names at WABEL8499IPM101 instead of just WABEL8499IPM1.
Input file example:
ColumnA (BASE NAME) ColumnB (QUANTITY)
WABEL8499IPM 2
Script:
SRCFILE="~/Desktop/deviceinfo.csv"
LOGDIR="~/Desktop/"
LOGFILE="$LOGDIR/DeviceNames.csv"
# base name, such as "WABEL8499IPM"
device_name=$1
# quantity, such as "2"
quantityNum=$2
# the largest in sequence, such as "WABEL8499IPM108"
max_sequence_name=$(cat $SRCFILE | grep -o -e "$device_name[0-9]*" | sort --reverse | head -n 1)
# extract the last 3digit number (such as "108") from max_sequence_name
max_sequence_num=$(echo $max_sequence_name | rev | cut -c 1-3 | rev)
# create new sequence_name
# such as ["WABEL8499IPM109", "WABEL8499IPM110"]
array_new_sequence_name=()
for i in $(seq 1 $quantityNum);
do
cnum=$((max_sequence_num + i))
array_new_sequence_name+=($(echo $device_name$cnum))
done
#CODE FOR CREATING OUTPUT FILE HERE
#for fn in ${array_new_sequence_name[#]}; do touch $fn; done;
# write log
for sqn in ${array_new_sequence_name[#]};
do
echo $sqn >> $LOGFILE
done
Usage:
bash test.sh WABEL8499IPM 2
Result in the log file:
WABEL8499IPM109
WABEL8499IPM110
Just wrap a loop around your code instead of assuming the args come in on the command line.
SRCFILE="~/Desktop/deviceinfo.csv"
LOGDIR="~/Desktop/"
LOGFILE="$LOGDIR/DeviceNames.csv"
while read device_name quantityNum
do max_sequence_name=$( grep -o -e "$device_name[0-9]*" $SRCFILE |
sort --reverse | head -n 1)
max_sequence_num=${max_sequence_name: -3}
array_new_sequence_name=()
for i in $(seq 1 $quantityNum)
do cnum=$((max_sequence_num + i))
array_new_sequence_name+=("$device_name$cnum")
done
for sqn in ${array_new_sequence_name[#]};
do echo $sqn >> $LOGFILE
done
done < input.file
I'd maybe pass the input file as the parameter now.
This is my simple shell script
root#Ubuntu:/tmp# cat -n script.sh
1 echo
2 while x= read -n 1 char
3 do
4 echo -e "Original value = $char"
5 echo -e "Plus one = `expr $char + 1`\n"
6 done < number.txt
7 echo
root#Ubuntu:/tmp#
And this is the content of number.txt
root#Ubuntu:/tmp# cat number.txt
12345
root#Ubuntu:/tmp#
As you can see on the code, I'm trying to read each number and process it separately. In this case, I would like to add one to each of them and print it on a new line.
root#Ubuntu:/tmp# ./script.sh
Original value = 1
Plus one = 2
Original value = 2
Plus one = 3
Original value = 3
Plus one = 4
Original value = 4
Plus one = 5
Original value = 5
Plus one = 6
Original value =
Plus one = 1
root#Ubuntu:/tmp#
Everything looks fine except for the last line. I've only have 5 numbers, however it seems like the code is processing additional one.
Original value =
Plus one = 1
Question is how does this happen and how to fix it?
It seems the input file number.txt contains a complete line, which is terminated by a line feed character (LF). (You can verify the input file is longer than 5 using ls -l.) read eventually encounters the LF and gives you an empty char (stripping the terminating LF from the input as it would without the -n option). This will give you expr + 1 resulting in 1. You can explicitely test for the empty char and terminate the while loop using the test -n for non-zero length strings:
echo "12345" | while read -n 1 char && [ -n "$char" ]; do echo "$char" ; done
I am currently building a bash script for class, and I am trying to use the grep command to grab the values from a simple calculator program and store them in the variables I assign, but I keep receiving a syntax error message when I try to run the script. Any advice on how to fix it? my script looks like this:
#!/bin/bash
addanwser=$(grep -o "num1 + num2" Lab9 -a 5 2)
echo "addanwser"
subanwser=$(grep -o "num1 - num2" Lab9 -s 10 15)
echo "subanwser"
multianwser=$(grep -o "num1 * num2" Lab9 -m 3 10)
echo "multianwser"
divanwser=$(grep -o "num1 / num2" Lab9 -d 100 4)
echo "divanwser"
modanwser=$(grep -o "num1 % num2" Lab9 -r 300 7)
echo "modawser"`
You want to grep the output of a command.
grep searches from either a file or standard input. So you can say either of these equivalent:
grep X file # 1. from a file
... things ... | grep X # 2. from stdin
grep X <<< "content" # 3. using here-strings
For this case, you want to use the last one, so that you execute the program and its output feeds grep directly:
grep <something> <<< "$(Lab9 -s 10 15)"
Which is the same as saying:
Lab9 -s 10 15 | grep <something>
So that grep will act on the output of your program. Since I don't know how Lab9 works, let's use a simple example with seq, that returns numbers from 5 to 15:
$ grep 5 <<< "$(seq 5 15)"
5
15
grep is usually used for finding matching lines of a text file. To actually grab a part of the matched line other tools such as awk are used.
Assuming the output looks like "num1 + num2 = 54" (i.e. fields are separated by space), this should do your job:
addanwser=$(Lab9 -a 5 2 | awk '{print $NF}')
echo "$addanwser"
Make sure you don't miss the '$' sign before addanwser when echo'ing it.
$NF selects the last field. You may select nth field using $n.
I'm trying to join 2 variables under loop but I cant get it to work..
My script lists newly added movies. I'm trying to make an output in excel that is clickable. Long story short, I need the script to list the 2 variables like this:
ab
ab
Right now it's doing this
a
a
b
b
This is the code
NEW_MOVIES_DIRLIST=''
for i in $(seq 1 ${NEW_MOVIES_COUNT}); do
MOVIE_PATH=$(echo -e "${NEW_MOVIES_LIST}" | sed -n "${i}p")
NEW_MOVIES_DIRLIST+="$(dirname "${MOVIE_PATH}")/\n"
done
LINKNAME=$(echo -e "${NEW_MOVIES_DIRLIST}" | sed -r 's,FOLTERS_TO_BE_SCANNED/HDD-EXTENDED.-SD./,,g')
NEW_MOVIES_DIRLIST=$(echo -e "${NEW_MOVIES_DIRLIST}" | sed '/^$/d')
NEW_MOVIES_COUNT=$(echo "${NEW_MOVIES_DIRLIST}" | wc -l)
NEW_MOVIES_LIST=''
for ((i = 0; i < ${NEW_MOVIES_COUNT}; i++))
do echo ${NEW_MOVIES_DIRLIST}${LINKNAME}
done
echo "Found ${NEW_MOVIES_COUNT} movies and ${NEW_SERIALS_COUNT} serials!"
${NEW_MOVIES_LIST}
The 2 variables are NEW_MOVIES_DIRLIST and LINKNAME, I can't join them when I run it. Any idea why?
You are adding a newline to the end of the string in the sed. So strip the newline before you display it.
newline=$'\n'
echo "${NEW_MOVIES_DIRLIST//$newline//}$LINKNAME"
I am having two files numbers.txt(1 \n 2 \n 3 \n 4 \n 5 \n) and alpha.txt (a \n n \n c \n d \n e \n)
Now I want to iterate both the files at the same time something like.
for num in `cat numbers.txt` && alpha in `cat alpha.txt`
do
echo $num "blah" $alpha
done
Or other idea I was having is
for num in `cat numbers.txt`
do
for alpha in `cat alpha.txt`
do
echo $num 'and' $alpha
break
done
done
but this kind of code always take the first value of $alpha.
I hope my problem is clear enough.
Thanks in advance.
Here it is what I actually intended to do. (Its just an example)
I am having one more file say template.txt having content.
variable1= NUMBER
variable2= ALPHA
I wanted to take the output from two files i.e numbers.txt and alpha.txt(one line from both at a time) and want to replace the NUMBER and ALPHA with the respective content from those two files.
so here it what I did as i got to know how to iterate both files together.
paste number.txt alpha.txt | while read num alpha
do
cp template.txt temp.txt
sed -i "{s/NUMBER/$num/g}" temp.txt
sed -i "{s/ALPHA/$alpha/g}" temp.txt
cat temp.txt >> final.txt
done
Now what i am having in final.txt is:
variable1= 1
variable2= a
variable1= 2
variable2= b
variable1= 3
variable2= c
variable1= 4
variable2= d
variable1= 5
variable2= e
variable1= 6
variable2= f
variable1= 7
variable2= g
variable1= 8
variable2= h
variable1= 9
variable2= i
variable1= 10
variable2= j
Its very simple and stupid approach. I wanted to know is there any other way to do this??
Any suggestion will be appreciated.
No, your question isn't clear enough. Specifically, the way you wish to iterate through your files is unclear, but assuming you want to have an output such as:
1 blah a
2 blah b
3 blah c
4 blah d
5 blah e
you can use the paste utility, like this:
paste number.txt alpha.txt | while read alpha num ; do
echo "$num and $alpha"
done
or even:
paste -d# alpha num | sed 's/#/ blah /'
Your first loop is impossible in bash. Your second one, without the break, would combine each line from numbers.txt with each line from alpha.txt, like this:
1 AND a
1 AND n
1 AND c
...
2 AND a
...
3 AND a
...
4 AND a
...
Your break makes it skip all lines from the alpha.txt, except the 1st one (bmk has already explained it in his answer)
It should be possible to organize the correct loop using the while loop construction, but it would be rather ugly.
There're lots of easier alternatives which maybe a better choice, depending on specifics of your task. For example, you could try this:
paste numbers.txt alpha.txt
or, if you really want your "AND"s, then, something like this:
paste numbers.txt alpha.txt | sed 's/\t/ AND /'
And if your numbers are really sequential (and you can live without 'AND'), you can simply do:
cat -n alpha.txt
Here is an alternate solution according to the first model you suggested:
while read -u 5 a && read -u 6 b
do
echo $a $b
done 5<numbers.txt 6<alpha.txt
The notation 5<numbers.txt tells the shell to open numbers.txt using file descriptor 5. read -u 5 a means read from a value for a from file descriptor 5, which has been associated with numbers.txt.
The advantage of this approach over paste is that it gives you fine-grain control over how you merge the two files. For example you could read one line from the first file and twice from the second file.
In your second example the inner loop is executed only once because of the break. It will simply jump out of the loop, i.e. you will always only get the first element of alpha.txt. Therefore I think you should remove it:
for num in `cat numbers.txt`
do
for alpha in `cat alpha.txt`
do
echo $num 'and' $alpha
done
done
If multiple loop isn't specifically your requirement but getting corresponding lines is then you may try the following code:
for line in `cat numbers.txt`
do
echo $line "and" $(cat alpha.txt| head -n$line | tail -n1 )
done
The head gets you the number of lines equal to the value of line and tail gets you the last element.
#tollboy, I think the answer you are looking for is this:
count=1
for item in $(paste number.txt alpha.txt); do
if [[ "${item}" =~ [a-zA-Z] ]]; then
echo "variable${count}= ${item}" >> final.txt
elif [[ "${item}" =~ [0-9] ]]; then
echo "variable${count}= ${item}" >> final.txt
fi
count=$((count+1))
done
When you type paste number.txt alpha.txt in your console, you see:
1 a
2 b
3 c
4 d
5 e
6 f
7 g
8 h
9 i
10 j
From bash's point of view $(paste number.txt alpha.txt) it looks like this:
1 a 2 b 3 c 4 d 5 e 6 f 7 g 8 h 9 i 10 j
So for each item in that list, figure out if it is alpha or numeric, and print it to the output file.
Lastly, increment the count.