I need to run a random script in a folder. I can use 'ls -1 /home/sepinto/EML-Samples/scripts/regular | sort -R | head -1' to get a random file name but how can I execute it?
Thanks
I can use 'ls -1 /home/sepinto/EML-Samples/scripts/regular | sort -R | head -1' to get a random file name but how can I execute it?
First, change your ls command to list the files with complete path, then just execute them either directly with backticks or storing them in a variable.
SCRIPTNAME=`ls -1 /home/sepinto/EML-Samples/scripts/regular/*.sh | sort -R | head -1`
echo "Executing $SCRIPTNAME"
"$SCRIPTNAME"
The above assumes that all your files have a .sh ending, change the ls argument if this is not the case.
It depends on the shell you are using.
I will assume your shell is bash or sh and the scripts are already executable.
Then all you need to do is enclose your command line above in backticks.
Everything you type between backticks is evaluated (executed) by the shell and then replaced by the command's output.
`ls -1 /home/sepinto/EML-Samples/scripts/regular | sort -R | head -1`
Edit:
Turns out that the path is stripped if ls -1 is piped into another command.
A solution is to store the path in a variable so you can use it twice:
d="/home/sepinto/EML-Samples/scripts/regular"; $d/`ls -1 $d/ | sort -R | head -1`
Related
I want to have a single command, not a script, that I can use to define a variable as a command output and then put that output into other commands. My best guess as to what that would look like is this:
LIST=$(ls) | head -1 | echo "${LIST}"
One reason that I want to do this is so that I can create a command that can find the pid of a program and then kill that pid. My best try doing that is:
DiscPid=$(ps -e | grep Discord | cut -b 1-5 | head -1 \ ) | kill "${DiscPid}"
But I'm not able to get this to work
I'm still relatively new to Linux and Bash so any help would be appreciated
Use a semicolon after setting the variable: var=foo; echo $var
You don't need piping here
DiscPid=$(code) | kill "${DiscPid}"
Change '|' to ';' and this one '\' also spare
DiscPid=$(ps -e | grep Discord | cut -b 1-5 | head -1); kill "${DiscPid}"
I am new to linux. I have a folder with many files in it and i need to get the latest file depending on the file name. Example: I have 3 files RAT_20190111.txt RAT_20190212.txt RAT_20190321.txt . I need a linux command to move the latest file here RAT20190321.txt to a specific directory.
If file pattern remains the same then you can try below command :
mv $(ls RAT*|sort -r|head -1) /path/to/directory/
As pointed out by #wwn, there is no need to use sort, Since the files are lexicographically sortable ls should do the job already of sorting them so the command will become :
mv $(ls RAT*|tail -1) /path/to/directory
The following command works.
ls | grep -v '/$' |sort | tail -n 1 | xargs -d '\n' -r mv -- /path/to/directory
The command first splits output of ls with newline. Then sorts it, takes the last file and then it moves this to the required directory.
Hope it helps.
Use the below command
cp ls |tail -n 1 /data...
I am trying to get the second file, when file contents sorted in reverse (desc order) and copy it to my local directory using scp
Here's what I got:
scp -r uname#host:./backups/dir1/$(ls -r | head -2| tail -1) /tmp/data_sync/dir1/
I still seem to copy all the files when I run this script. What am I missing? TIA.
The $(...) is being interpreted locally. If you want the commands to run on the remote, you'll need to use ssh and have the remote side use scp to copy files to your local system.
Since parsing ls's output has a number of problems, I'll use find to accomplish the same thing as ls, telling it to use NUL between each filename rather than newline. sort sorts that list of filenames, and sed -n 2p prints the second element of the sorted list of filenames. xargs runs the scp command, inserting the filename as the first argument.
ssh uname#host "find ./backups/dir1/ -mindepth 1 -maxdepth 1 -name '[^.]*' -print0 | \
sort -r -z | sed -z -n 2p | \
xargs -0 -I {} scp {} yourlocalhost:/tmp/data_sync/dir1/"
If I got your question, your command is ok with just one specification:
you first ran scp -r which recursively scps your files which have theri content sorted in reverse order.
Try without -r:
scp uname#host:./backups/dir1/$(ls -r | head -2 | tail -1) /tmp/data_sync/dir1/
The basic syntax for scp is:
scp username#source:/location/to/file username#destination:/where/to/put
Don't forget that -rrecursively copy entire directories. More, note that scp follows symbolic links encountered in the tree traversal.
Here is what I am trying to achieve. I want to run a sequence of commands on that file, so for example
ls * | xargs (cat - | calculateforfile)
I want to run (cat | calculateforthisfile) on each of the file separately. So basically, how to group a list of commands as if it is one single function?
No need to use xargs. Just use a loop. You also don't need to use cat. Just redirect its input with the file.
for A in *; do
calculateforfile < "$A"
done
As a single line:
for A in *; do calculateforfile < "$A"; done
If you're looking for xargs solution for this (for example find command)
find . -name "*.txt" | xargs -I % cat %
This will cat all the files found under current directory that end in .txt
The -I option is the key there
I want to store the result of a command to a variable in my shell script. I cant seem to get it to work. I want the most recently dated file in the directory.
PRODUCT= 'ls -t /some/dir/file* | head -1 | xargs -n1 basename'
it wont work
you have two options, either $ or backsticks`.
1) x=$(ls -t /some/dir/file* | head -1 | xargs -n1 basename)
or
2) x=`ls -t /some/dir/file* | head -1 | xargs -n1 basename`
echo $x
Edit: removing unnecessary bracket for (2).
The problem that you're having is that the command needs to be surrounded by back-ticks rather than single quotes. This is known as 'Command Substitution'.
Bash allows you to use $() for command substitution, but this is not available in all shells. I don't know if it's available in KSH; if it is, it's probably not available in all versions.
If the $() syntax is available in your version of ksh, you should definitely use it; it's easier to read (back ticks are too easy to confuse with single quotes); back-ticks are also hard to nest.
This only addresses one of the problems with your command, however: ls returns directories as well as files, so if the most recent thing modified in the specified directory is a sub-directory, that is what you will see.
If you only want to see files, I suggest using some version of the following (I'm using Bash, which supports default variables, you'll probably have to play around with the syntax of $1)
lastfile ()
{
find ${1:-.} -maxdepth 1 -type f -printf "%T+ %p\n" | sort -n | tail -1 | sed 's/[^[:space:]]\+ //'
}
This runs find on the directory, and only pulls files from that directory. It formats all of the files like this:
2012-08-29+16:21:40.0000000000 ./.sqlite_history
2013-01-14+08:52:14.0000000000 ./.davmail.properties
2012-04-04+16:16:40.0000000000 ./.DS_Store
2010-04-21+15:49:00.0000000000 ./.joe_state
2008-09-05+17:15:28.0000000000 ./.hplip.conf
2012-01-31+13:12:28.0000000000 ./.oneclick
sorts the list, takes the last line, and chops off everything before the first space.
You want $() (preferred) or backticks (``) (older style), rather than single quotes:
PRODUCT=$(ls -t /some/dir/file* | head -1 | xargs -n1 basename)
or
PRODUCT=`ls -t /some/dir/file* | head -1 | xargs -n1 basename`
You need both quotes to ensure you keep the name even if it contains spaces, and also in case you later want more than 1 file, and "$(..)" to run commands in background
I believe you also need the '-1' option to ls, otherwise you could have several names per lines (you only keep 1 line, but it could be several files)
PRODUCT="$(ls -1t /some/dir/file* | head -1 | xargs -n1 basename)"
Please do not put space around the "=" variable assignments (as I saw on other solutions here) , as it's not very compatible as well.
I would do something like:
Your version corrected:
PRODUCT=$(ls -t /some/dir/file* | head -1 | xargs -n1 basename)
Or simpler:
PRODUCT=$(cd /some/dir && ls -1t file* | head -1)
change to the directory
list one filename per line and sort by time/date
grab the first line