I am working on the logs, they are in multiple number.
lets assume the following files has the content
file1
1
file2
2
file3
3
by using the command cat file* the result would be
1
2
3
but i am looking for some thing , while i use the regex/command using file* i want the output to be some thing like this.
3
2
1
could some one help me please.
Pass the output of cat to tac :
$ cat file*
1
2
3
$ cat file* | tac
3
2
1
You may call
ls -1r file* | xargs cat
in order to specify the order of the files. Its output is different from the tac solution, since each single logfile is in the correct order. (Perhaps this is not even the desired output).
Related
I have a file, leading with numbers:
$ cat file
1
3
13
2
4
12
When I use cat file | sort, it displays like this:
$ cat file | sort
1
12
13
2
3
4
How can I get the answer like this:
1
2
3
4
12
13
Use the -n option to enable numerical sorting:
$ cat file | sort -n
This is faster and more portable than -g, which is a proprietary extension of GNU sort.
Use -g option of sort for general sorting of numbers (can be slow for large inputs):
$ sort -g file
or:
$ sort -n file
The difference can be found in a related question.
UPD: Fixed the useless cat as stated in comments.
While executing,
$ls -1rt /directory | head -n 3
file1.txt
file2.txt
file3.txt
$ls -1rt /directory | tail -n 3
file2.txt
file3.txt
Could anyone tell me how the tail and head works internally during file listing and why this difference in no.of files?
Thanks in advance
head lists a certain amount of lines of your file. It won’t read it integraly, just the few first lines. tail does exactly the same thing, but starts at the end of the file. The -n 3 parameter is here to stop reading after 3 lines, then prints them only.
Suppose I am staying in currenty directory, I wanted to list all the files in total numbers, as well as the size, permission, and also the number of files by types.
here is the sample outputs:
Here is a sample :
Print information about "/home/user/poker"
total number of file : 83
pdf files : 5
html files : 9
text files : 15
unknown : 5
NB: anyfile without extension could be consider as unknown.
i hope to use some simple command like ls, cut, sort, unique ,(just examples) put each different extension in file and using wc -l to count number of lines
or do i need to use grep, awk , or something else?
Hope to get the everybody's advices.thank you!
Best way is to use file to output only mimetype and pass it to awk.
file * -ib | awk -F'[;/.]' '{print $(NF-1)}' | sort -n | uniq -c
On my home directory it produces this output.
35 directory
3 html
1 jpeg
1 octet-stream
1 pdf
32 plain
5 png
1 spreadsheet
7 symlink
1 text
1 x-c++
3 x-empty
1 xml
2 x-ms-asf
4 x-shellscript
1 x-shockwave-flash
If you think text/x-c++ and text/plain should be in same Use this
file * -ib | awk -F'[;/.]' '{print $1}' | sort -n | uniq -c
6 application
6 image
45 inode
40 text
2 video
Change the {print $1} part according to your need to get the appropriate output.
You need bash.
files=(*)
pdfs=(*.pdf)
echo "${#files[#]}"
echo "${#pdfs[#]}"
echo "$((${#files[#]}-${#pdfs[#]}))"
find . -type f | xargs -n1 basename | fgrep . | sed 's/.*\.//' | sort | uniq -c | sort -n
That gives you a recursive list of file extensions. If you want only the current directory add a -maxdepth 1 to the find command.
I am using ls -l -t to get a list of files in a directory ordered by time.
I would like to limit the search result to the top 2 files in the list.
Is this possible?
I've tried with grep and I struggled.
You can pipe it into head:
ls -l -t | head -3
Will give you top 3 lines (2 files and the total).
This will just give you the first 2 lines of files, skipping the size line:
ls -l -t | tail -n +2 | head -2
tail strips the first line, then head outputs the next 2 lines.
To avoid dealing with the top output line you can reverse the sort and get the last two lines
ls -ltr | tail -2
This is pretty safe, but depending what you'll do with those two file entries after you find them, you should read Parsing ls on the problems with using ls to get files and file information.
Or you could try just this
ls -1 -t | head -2
The -1 switch skips the title line.
You can use the head command to grab only the first two lines of output:
ls -l -t | head -2
You have to pipe through head.
ls -l -t | head -n 3
will output the two first results.
Try this:
ls -td -- * | head -n 2
How can I display only different rows using diff in a separate file?
For example, the file number 1 contains the line:
1;john;125;3
1;tom;56;2
2;jack;10;5
A file number 2 contains the following lines:
1;john;125;3
1;tom;58;2
2;jack;10;5
How to make in the following happen?
1;tom;58;2
a.txt:
1;john;125;3
1;tom;56;2
2;jack;10;5
b.txt:
1;john;125;3
1;tom;58;2
2;jack;10;5
Use comm:
comm -13 a.txt b.txt
1;tom;58;2
The command line options to comm are pretty straight-forward:
-1 suppress column 1 (lines unique to FILE1)
-2 suppress column 2 (lines unique to FILE2)
-3 suppress column 3 (lines that appear in both files)
Here's a simple solution that I think is better than diff:
sort file1 file2 | uniq -u
sort file1 file2 concatenates the two files and sorts it
uniq -u prints the unique lines (that do not repeat). It requires the input to be pre-sorted.
Assuming you want to retain only the lines unique to file 2 you can do:
comm -13 file1 file2
Note that the comm command expects the two files to be in sorted order.
Using group format specifiers you can suppress printing of unchanged lines and print only changed lines for changed
diff --changed-group-format="%>" --unchanged-group-format="" file1 file2