I have a few files in a directory with names similar to
_system1.log
_system2.log
_system3.log
other.log
but they are not created in that order.
Is there a simple, non-hardcoded, way to cat the files starting with the underscore in date order?
Quick 'n' dirty:
cat `ls -t _system*.log`
Safer:
ls -1t _system*.log | xargs -d'\n' cat
Use ls:
ls -1t | xargs cat
ls -1 | xargs cat
You can concatenate and also store them in a single file according to their time of creation and also you can specify the files which you want to concatenate. Here, I find it very useful. The following command will concatenate the files which are arranged according to their time of creaction and have common string 'xyz' in their file name and store all of them in outputfile.
cat $(ls -t |grep xyz)>outputfile
Related
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 have two directories with files in them. Directory A contains a list of photos with numbered endings (e.g. janet1.jpg laura2.jpg) and directory B has the same files except with different numbered endings (e.g. janet41.jpg laura33.jpg). How do I find the files that do not have a corresponding file from directory A and B while ignoring the numbered endings? For example there is a rachael3 in directory A but no rachael\d in directory B. I think there's a way to do with the diff command in bash but I do not see an obvious way to do it.
I can't see a way to use diff for this directly. It will probably be easier to use a sums tool (md5, sha1, etc.) on both directories and then sort both files based on the first (sum) column and diff/compare those output files.
Alternatively, something like findimagedupes (which isn't as simple a comparison as diff or a sums check) might be a simpler (and possibly more useful) solution.
It seems you know that your files are the same, if they exist and you are sure, there is only one of a kind per directory.
So to diff the contents of the directory according to this, you need to get only the relevant parts of the file name ("laura", "janet").
This could be done by simple grepping the appropriate parts from the output of ls like this:
ls dir1/ | egrep -o '^[a-A]+'
Then to compare, let's say dir1 and dir2, you can use:
diff <(ls dir1/ | egrep -o '^[a-A]+') <(ls dir2/ | egrep -o '^[a-A]+')
Assuming the files are simply renamed and otherwise identical, a simple solution to find the missing ones is to use md5sum (or sha or somesuch) and uniq:
#!/bin/bash
md5sum A/*.jpg B/*.jpg >index
awk '{print $1}' <index | sort >sums # delete dir/file
# list unique files (missing from one directory)
uniq -u sums | while read s; do
grep "$s" index | sed 's/^[a-z0-9]\{32\} //'
done
This fails in the case where a folder contains several copies of the same file renamed (such that the hash matches multiple files in one folder), but that is easily fixed:
#!/bin/bash
md5sum A/*.jpg B/*.jpg > index
sed 's/\/.*//' <index | sort >sums # just delete /file
# list unique files (missing from one directory)
uniq sums | awk '{print $1}' |\
uniq -u | while read s junk; do
grep "$s" index | sed 's/^[a-z0-9]\{32\} //'
done
I'm creating a list of file-names using the command:
ls | grep "\.txt$"
I'm getting a list of files:
F1.txt
F2.txt
F3.txt
F4.txt
I want to view the content of these files (using less / more / cat /...)
is there a way to do this by pipping?
(Btw, I got a list of file-names using a more complex command, this is just a simpler example for clarification)
Would this be enough?
$ cat *txt
For richer queries, you could use find and xargs:
$ find . -name "*txt" | xargs cat
you can try something like this:
#!/bin/bash
for i in *.txt
do
echo Displaying file $i ...
more $i
done
What about:
cat $(ls | grep "\.txt$")
I have a directory structure containing some files. I'm trying to find the names of top directories that do contain a file with specific string in it.
I've got this:
grep -r abcdefg . | grep commit_id | sed -r 's/\.\/(.+)\/.*/\1/';
Which returns something like:
topDir1
topDir2
topDir3
I would like to be able to take this output and somehow feed it into this command:
ls -t | grep -e topDir1 -e topDir2 -e topDir3
which would returned the output filtered by the first command and ordered by modification date.
I'm hoping for a one liner. Or maybe there is a better way of doing it?
This should work as long as none of the directory names contain whitespace or wildcard characters:
ls -td $(grep -r abcdefg . | grep commit_id | dirname)
How do I pipe the output of grep as the search pattern for another grep?
As an example:
grep <Search_term> <file1> | xargs grep <file2>
I want the output of the first grep as the search term for the second grep. The above command is treating the output of the first grep as the file name for the second grep. I tried using the -e option for the second grep, but it does not work either.
You need to use xargs's -i switch:
grep ... | xargs -ifoo grep foo file_in_which_to_search
This takes the option after -i (foo in this case) and replaces every occurrence of it in the command with the output of the first grep.
This is the same as:
grep `grep ...` file_in_which_to_search
Try
grep ... | fgrep -f - file1 file2 ...
If using Bash then you can use backticks:
> grep -e "`grep ... ...`" files
the -e flag and the double quotes are there to ensure that any output from the initial grep that starts with a hyphen isn't then interpreted as an option to the second grep.
Note that the double quoting trick (which also ensures that the output from grep is treated as a single parameter) only works with Bash. It doesn't appear to work with (t)csh.
Note also that backticks are the standard way to get the output from one program into the parameter list of another. Not all programs have a convenient way to read parameters from stdin the way that (f)grep does.
I wanted to search for text in files (using grep) that had a certain pattern in their file names (found using find) in the current directory. I used the following command:
grep -i "pattern1" $(find . -name "pattern2")
Here pattern2 is the pattern in the file names and pattern1 is the pattern searched for
within files matching pattern2.
edit: Not strictly piping but still related and quite useful...
This is what I use to search for a file from a listing:
ls -la | grep 'file-in-which-to-search'
Okay breaking the rules as this isn't an answer, just a note that I can't get any of these solutions to work.
% fgrep -f test file
works fine.
% cat test | fgrep -f - file
fgrep: -: No such file or directory
fails.
% cat test | xargs -ifoo grep foo file
xargs: illegal option -- i
usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]
[-L number] [-n number [-x]] [-P maxprocs] [-s size]
[utility [argument ...]]
fails. Note that a capital I is necessary. If i use that all is good.
% grep "`cat test`" file
kinda works in that it returns a line for the terms that match but it also returns a line grep: line 3 in test: No such file or directory for each file that doesn't find a match.
Am I missing something or is this just differences in my Darwin distribution or bash shell?
I tried this way , and it works great.
[opuser#vjmachine abc]$ cat a
not problem
all
problem
first
not to get
read problem
read not problem
[opuser#vjmachine abc]$ cat b
not problem xxy
problem abcd
read problem werwer
read not problem 98989
123 not problem 345
345 problem tyu
[opuser#vjmachine abc]$ grep -e "`grep problem a`" b --col
not problem xxy
problem abcd
read problem werwer
read not problem 98989
123 not problem 345
345 problem tyu
[opuser#vjmachine abc]$
You should grep in such a way, to extract filenames only, see the parameter -l (the lowercase L):
grep -l someSearch * | xargs grep otherSearch
Because on the simple grep, the output is much more info than file names only. For instance when you do
grep someSearch *
You will pipe to xargs info like this
filename1: blablabla someSearch blablabla something else
filename2: bla someSearch bla otherSearch
...
Piping any of above line makes nonsense to pass to xargs.
But when you do grep -l someSearch *, your output will look like this:
filename1
filename2
Such an output can be passed now to xargs
I have found the following command to work using $() with my first command inside the parenthesis to have the shell execute it first.
grep $(dig +short) file
I use this to look through files for an IP address when I am given a host name.