when I'm configuring grub2 to unlock an LVM root (rd.luks.name=UUID=cryptroot) I usually just blkid /dev/nvme0n1p3 >> uuid, edit the text and delete all the data that isn't the UUID, and then :r uuid to insert it to the grub config in vim. I know there has to be an easier way to do this with sed but so far the closest I've gotten is as follows:
➜ ~ blkid /dev/nvme0n1p3
/dev/nvme0n1p3: UUID="2276de2b-9370-4577-90ea-3b0191ebea4e"
TYPE="crypto_LUKS" PARTUUID="b7a643ce-8bca-418f-a631-b0fc8648432c"
➜ ~ blkid /dev/nvme0n1p3 | sed 's/.*UUID="\(.*\)" .*/\1/'
2276de2b-9370-4577-90ea-3b0191ebea4e" TYPE="crypto_LUKS
Anyone have any idea what I could add to the sed arguments to get rid of everything after the end of the UUID including that quotation mark?
blkid -s UUID -o value /dev/nvme0n1p3
or
lsblk -n -o UUID /dev/nvme0n1p3
Output:
2276de2b-9370-4577-90ea-3b0191ebea4e
See: man blkid
Related
I have a big file which is composed of alot of different lines which only have one commen keyword, storaged.
PROC:storage123:0702:2108:0,1,2,3,4,5:storage:vers:storaged:storage123:Storage
123:storage123:-R /etc/orc/storage123 -e emr123#localhost -p Xxx::
PROC:storageabc:0606:2108:0,1,2,3,4,5:storage:vers:storaged:storageabc:Storage
abc:storageabc: -e emabc#localhost -R /etc/orc/storageabc -p 654::
What i need to do is grep for the path that can be found on all storaged keywords that comes after -R. But I only want the path, nothing after that. -R can be found on different places so there is no pattern to it.
I created one espressionen which seemed to work, but I think I made it much for complex (and not 100% sure to match) than it should have to be.
[root:~/scripts/] <conf.txt grep -o 'R *[^ ]*' | grep -o '[^ ]*$' | sed 's/.*R\///'
/etc/orc/storage123
/etc/orc/storagerabc
The espression also is hard to implement in a bash script so something simpler would be great. I need these paths in the script later on.
Cheers
Your attempt is nice, but you can simplify it by using a look-behind:
$ grep -Po '(?<=-R )[^ ]*' file
/etc/orc/storage123
/etc/orc/storageabc
Basically it looks for the string -R (note the space) and from that, it prints everything up to a space.
$ sed 's/.*-R \([^ ]*\).*/\1/' file
/etc/orc/storage123
/etc/orc/storageabc
I want to filter the output of the blkid to get the UUID.
The output of blkid looks like
CASE 1:-
$ blkid
/dev/sda2: LABEL="A" UUID="4CC9-0015"
/dev/sda3: LABEL="B" UUID="70CF-169F"
/dev/sda1: LABEL=" NTFS_partition" UUID="3830C24D30C21234"
In somecases the output of blkid looks like
CASE 2:-
$ blkid
/dev/sda1: UUID="d7ec380e-2521-4fe5-bd8e-b7c02ce41601" TYPE="ext4"
/dev/sda2: UUID="fc54f19a-8ec7-418b-8eca-fbc1af34e57f" TYPE="ext4"
/dev/sda3: UUID="6f218da5-3ba3-4647-a44d-a7be19a64e7a" TYPE="swap"
I want to filter out the UUID.
Using the combination of grep and cut it can be done as
/sbin/blkid | /bin/grep 'sda1' | /bin/grep -o -E 'UUID="[a-zA-Z|0-9|\-]*' | /bin/cut -c 7-
I have tried using awk , grep and cut as below for filtering the UUID
$ /sbin/blkid | /bin/grep 'sda1' | /usr/bin/awk '{print $2}' | /bin/sed 's/\"//g' | cut -c 7-
7ec380e-2521-4fe5-bd8e-b7c02ce41601
The above command(which uses awk) is not reliable since sometimes an extra field such as LABEL may be present in the output of the blkid program as shown in the above output.
What is the best way to create a command using awk which works reliably?
Please post if any other elegant method exits for the job using bin and core utils. I dont want to use perl or python since this has to be run on busybox.
NOTE:-I am using busybox blkid to which /dev/sda1 can not be passed as the args(the version i am using does not support it) hence the grep to filter the line.
UPDATE :- added the CASE 2: -output to show that field position can not be relied upon.
Why are you making it so complex?
Try this:
# blkid -s UUID -o value
d7ec380e-2521-4fe5-bd8e-b7c02ce41601
fc54f19a-8ec7-418b-8eca-fbc1af34e57f
6f218da5-3ba3-4647-a44d-a7be19a64e7a
Or this:
# blkid -s UUID -o value /dev/sda1
d7ec380e-2521-4fe5-bd8e-b7c02ce41601
Install proper blkid package if you don't have it:
sudo apt-get install util-linux
sudo yum install util-linux
For all the UUID's, you can do :
$ blkid | sed -n 's/.*UUID=\"\([^\"]*\)\".*/\1/p'
d7ec380e-2521-4fe5-bd8e-b7c02ce41601
fc54f19a-8ec7-418b-8eca-fbc1af34e57f
6f218da5-3ba3-4647-a44d-a7be19a64e7a
Say, only for a specific sda1:
$ blkid | sed -n '/sda1/s/.*UUID=\"\([^\"]*\)\".*/\1/p'
d7ec380e-2521-4fe5-bd8e-b7c02ce41601
The sed command tries to group the contents present within the double quotes after the UUID keyword, and replaces the entire line with the token.
Here's a short awk solution:
blkid | awk 'BEGIN{FS="[=\"]"} {print $(NF-1)}'
Output:
4CC9-0015
70CF-169F
3830C24D30C21234
Explanation:
BEGIN{FS="[=\"]"} : Use = and " as delimiters
{print $(NF-1)}: NF stands of Number of Fields; here we print the 2nd to last field
This is based on the consistent structure of blkid output: UUID in quotes is at the end of each line.
Alternatively:
blkid | awk 'BEGIN{FS="="} {print $NF}' | sed 's/"//g'
data.txt
/dev/sda2: LABEL="A" UUID="4CC9-0015"
/dev/sda3: LABEL="B" UUID="70CF-169F"
/dev/sda1: LABEL=" NTFS_partition" UUID="3830C24D30C21234"
awk and sed combination
cat data.txt | awk 'BEGIN{FS="UUID";RS="\n"} {print $2}' | sed -e 's/=//' -e 's/"//g'
Explanation:
Set the Field Separator to the string 'UUID', $2 will give the rest output
use sed then to remove the = and " as shown where -e is a switch so that you can give multiple sed commands/expression in one.
All occurrences of " are removed using the ending g option i.e. global.
The question has a "e.t.c" so I'm going to assume python is one of the options ;)
#!/usr/bin/env python3
import subprocess, re, json
# get blkid output
blkid = subprocess.check_output(["blkid"]).decode('utf-8')
devices = []
for line in [x for x in blkid.split('\n') if x]:
parameters = line.split()
for idx, parameter in enumerate(parameters):
if idx is 0:
devices.append({"DEVICE": re.sub(r':$','',parameter)})
continue
key_and_value = parameter.split('=')
devices[-1].update({
key_and_value[0]: re.sub(r'"','',key_and_value[1])
})
uuids = [{dev['DEVICE']: dev['UUID']} for dev in devices if 'UUID' in dev.keys()]
print(json.dumps(uuids, indent=4, sort_keys=True))
Although, this is probably overkill and quite a few error handling/optimization is missing from this script XD
I assume you're using busybox in an initramfs and you are waiting for your e.g. USB drive with the rootfs on it to become available.
You could use the following awk script (busybox awk compliant).
# cat get-ruuid.awk
BEGIN {
ruuid=ENVIRON["RUUID"]
}
/^\/dev\/sd[a-z]/ {
if (index($0, tolower(ruuid)) || index($0, toupper(ruuid))) {
split($1, parts, ":")
printf("%s\n", parts[1])
exit(0) # Return success and stop further scanning.
}
}
END {
exit(1) # If we reach the end, it means RUUID was not found.
}
Call it as follows from e.g. the init script; this is not the most ideal way.
# The UUID of your root partition
export RUUID="<put proper uuid value here>"
for x in 1, 2, 3, 4, 5 ; do
mdev -s
found=$(blkid | awk -f ./get-ruuid.awk)
test -z $found || break; # If no longer zero length, break the loop.
sleep 1
done
But if this is the only reason why you would want to have an initramfs, I would use the 'root=PARTUUID=... waitroot' Linux kernel command line option. Check the kernel docs and sources.
Get the proper PARTUUID (NOT UUID) of your root partition with the blkid command.
The terminal transcript speaks for itself:
iMac:~$ echo -n a | md5
0cc175b9c0f1b6a831c399e269772661
iMac:~$ perl -e 'system "echo -n a | md5"'
c3392e9373ccca33629d82b17699420f
Note that the MD5 hash of a is 0cc175b9c0f1b6a831c399e269772661, the first
result. Why does it turns out to be different when the same command is called
by perl?
By the way, perl is perl 5, version 12, subversion 4 (v5.12.4) built for darwin-thread-multi-2level. And the system: Mac OS 10.8, Darwin 12.0
When in the /bin/sh shell on mac, echo -n doesn't not print out the newline like it does in /bin/bash. You can see this if you drop into /bin/sh and run echo -n a, your output should look like this:
sh-3.2$ echo -n a
-n a
so you're literally getting -n a instead of the desired a. As perl system runs /bin/sh to evaluate your command, -n a is being passed into md5 instead of your desired a
The specific question has already been answered, but I want to point out that od is useful to help understand exactly what any command outputs or file contains. This is useful especially to show otherwise non-printing characters.
$ echo -n a | od -tc
0000000 a
0000001
$ perl -e 'system "echo -n a | od -tc";'
0000000 - n a \n
0000005
The following command is correctly changing the contents of 2 files.
sed -i 's/abc/xyz/g' xaa1 xab1
But what I need to do is to change several such files dynamically and I do not know the file names. I want to write a command that will read all the files from current directory starting with xa* and sed should change the file contents.
I'm surprised nobody has mentioned the -exec argument to find, which is intended for this type of use-case, although it will start a process for each matching file name:
find . -type f -name 'xa*' -exec sed -i 's/asd/dsg/g' {} \;
Alternatively, one could use xargs, which will invoke fewer processes:
find . -type f -name 'xa*' | xargs sed -i 's/asd/dsg/g'
Or more simply use the + exec variant instead of ; in find to allow find to provide more than one file per subprocess call:
find . -type f -name 'xa*' -exec sed -i 's/asd/dsg/g' {} +
Better yet:
for i in xa*; do
sed -i 's/asd/dfg/g' $i
done
because nobody knows how many files are there, and it's easy to break command line limits.
Here's what happens when there are too many files:
# grep -c aaa *
-bash: /bin/grep: Argument list too long
# for i in *; do grep -c aaa $i; done
0
... (output skipped)
#
You could use grep and sed together. This allows you to search subdirectories recursively.
Linux: grep -r -l <old> * | xargs sed -i 's/<old>/<new>/g'
OS X: grep -r -l <old> * | xargs sed -i '' 's/<old>/<new>/g'
For grep:
-r recursively searches subdirectories
-l prints file names that contain matches
For sed:
-i extension (Note: An argument needs to be provided on OS X)
Those commands won't work in the default sed that comes with Mac OS X.
From man 1 sed:
-i extension
Edit files in-place, saving backups with the specified
extension. If a zero-length extension is given, no backup
will be saved. It is not recommended to give a zero-length
extension when in-place editing files, as you risk corruption
or partial content in situations where disk space is exhausted, etc.
Tried
sed -i '.bak' 's/old/new/g' logfile*
and
for i in logfile*; do sed -i '.bak' 's/old/new/g' $i; done
Both work fine.
#PaulR posted this as a comment, but people should view it as an answer (and this answer works best for my needs):
sed -i 's/abc/xyz/g' xa*
This will work for a moderate amount of files, probably on the order of tens, but probably not on the order of millions.
Another more versatile way is to use find:
sed -i 's/asd/dsg/g' $(find . -type f -name 'xa*')
I'm using find for similar task. It is quite simple: you have to pass it as an argument for sed like this:
sed -i 's/EXPRESSION/REPLACEMENT/g' `find -name "FILE.REGEX"`
This way you don't have to write complex loops, and it is simple to see, which files you are going to change, just run find before you run sed.
u can make
'xxxx' text u search and will replace it with 'yyyy'
grep -Rn '**xxxx**' /path | awk -F: '{print $1}' | xargs sed -i 's/**xxxx**/**yyyy**/'
There's some good answers above. I thought I'd throw in one more that is succinct and parallelizable, using GNU parallel, which I often prefer to xargs:
parallel sed -i 's/abc/xyz/g' {} ::: xa*
Combine this with the -j N option to run N jobs in parallel.
If you are able to run a script, here is what I did for a similar situation:
Using a dictionary/hashMap (associative array) and variables for the sed command, we can loop through the array to replace several strings. Including a wildcard in the name_pattern will allow to replace in-place in files with a pattern (this could be something like name_pattern='File*.txt' ) in a specific directory (source_dir).
All the changes are written in the logfile in the destin_dir
#!/bin/bash
source_dir=source_path
destin_dir=destin_path
logfile='sedOutput.txt'
name_pattern='File.txt'
echo "--Begin $(date)--" | tee -a $destin_dir/$logfile
echo "Source_DIR=$source_dir destin_DIR=$destin_dir "
declare -A pairs=(
['WHAT1']='FOR1'
['OTHER_string_to replace']='string replaced'
)
for i in "${!pairs[#]}"; do
j=${pairs[$i]}
echo "[$i]=$j"
replace_what=$i
replace_for=$j
echo " "
echo "Replace: $replace_what for: $replace_for"
find $source_dir -name $name_pattern | xargs sed -i "s/$replace_what/$replace_for/g"
find $source_dir -name $name_pattern | xargs -I{} grep -n "$replace_for" {} /dev/null | tee -a $destin_dir/$logfile
done
echo " "
echo "----End $(date)---" | tee -a $destin_dir/$logfile
First, the pairs array is declared, each pair is a replacement string, then WHAT1 will be replaced for FOR1 and OTHER_string_to replace will be replaced for string replaced in the file File.txt. In the loop the array is read, the first member of the pair is retrieved as replace_what=$i and the second as replace_for=$j. The find command searches in the directory the filename (that may contain a wildcard) and the sed -i command replaces in the same file(s) what was previously defined. Finally I added a grep redirected to the logfile to log the changes made in the file(s).
This worked for me in GNU Bash 4.3 sed 4.2.2 and based upon VasyaNovikov's answer for Loop over tuples in bash.
The Silver Searcher Solution
I'm adding another option for those people who don't know about the amazing tool called The Silver Searcher (command line tool is ag).
Note: You can use grep and other tools to do the same thing here, but The Silver Searcher is fantastic :)
TLDR
ag -l 'abc' | xargs sed -i 's/abc/xyz/g'
Install The Silver Searcher
sudo apt install silversearcher-ag # Debian / Ubuntu
sudo pacman -S the_silver_searcher # Arch / EndeavourOS
sudo yum install epel-release the_silver_searcher # RHEL / CentOS
Demo Files
Paste the following into your terminal to create some demonstration files:
mkdir /tmp/food
cd /tmp/food
content="Everybody loves to abc this food!"
echo "$content" > ./milk
echo "$content" > ./bread
mkdir ./fastfood
echo "$content" > ./fastfood/pizza
echo "$content" > ./fastfood/burger
mkdir ./fruit
echo "$content" > ./fruit/apple
echo "$content" > ./fruit/apricot
Using 'ag'
The following ag command will recursively find all the files that contain the string 'abc'. It ignores the .git directory, .gitignore files, and other ignore files:
$ ag 'abc'
milk
1:Everybody loves to abc this food!
bread
1:Everybody loves to abc this food!
fastfood/burger
1:Everybody loves to abc this food!
fastfood/pizza
1:Everybody loves to abc this food!
fruit/apple
1:Everybody loves to abc this food!
fruit/apricot
1:Everybody loves to abc this food!
To just list the files that contain the string 'abc', use the -l switch:
$ ag -l 'abc'
bread
fastfood/burger
fastfood/pizza
fruit/apricot
milk
fruit/apple
Changing Multiple Files
Finally, using xargs and sed, we can replace the 'abc' string with another string:
ag -l 'abc' | xargs sed -i 's/abc/eat/g'
In the above command, ag is listing all the files that contain the string 'abc'. The xargs command is splitting the file names and piping them individually into the sed command.
perl -E '$i=#{[`zypper lr`]}-2;map{`zypper rr $_`}1..$i'
What would be a good way to write this perl-onliner in bash. ( I would like to remove all repositores with zypper)?
Here's a way to do this:
The first command counts the number of lines produced by zypper lr command.
So, you obtain that by:
COUNT_LINES=`zypper lr|tail +3|wc -l`
The second command merely runs zypper rr [NUMBER] for each number 1 through the counter; so you run the for loop in bash as shown in this SO question:
How do I iterate over a range of numbers in bash?
zypper lr | grep -P "^\d" | cut -d'|' -f 1 | xargs sudo zypper rr
But much easier to simply:
sudo rm -rf /etc/zypp/repos.d/*