I'm trying to use someone else's [c] code that controls a linux shell over a wireless usb device. It fopen-s files "IReadFromBash" and "IWriteToBash" in the current dir to communicate. It comes with no notes but obviously expects a special file to already exist to facilitate this, and segfaults without them. Is there some obvious way to create named in- and out-files that connect to a shell?
Really just a guess on my part but I suspect they'll be named pipes, created with mknod. That seems to me the best way to achieve the desired goal.
You can see this in operation here. From a terminal session:
pax> mknod infile p
pax> mknod outfile p
pax> bash <infile >outfile
Then, from another terminal:
pax> echo ls >infile
pax> cat outfile | sed 's/^/ /'
backup0.sh
backup1.sh
Desktop
Downloads
infile
Music
outfile
Pax
Pictures
Public
super_sekrit_porn
Templates
Videos
workspace
pax> _
Related
In a SSH PuTTY connection, I have a directory with a bunch of files - I want to exclude some of these files in a FOR loop operation - Specifically, I want to exclude any files that have the words "Parrot" or "Tiger" in their filename - The below gives me the list of files I'm looking for.
ls Zoo_Animals*sas |grep -vi Parrot |grep -vi Tiger
For context, normally filenames would appear like Zoo_Animals_Monkey_07.sas or Zoo_Animals_Lion_12.sas, etc.
So, If I'd like to run a command for ALL animals, I'd normally Unixuse:
for file in Zoo_Animals*.sas; do <command here> "$file"; done
BUT, I can't seem to figure out how to run this FOR loop while excluding the files for Tigers and Parrots.
Any help would be greatly appreciated!!
Embed your first command inside the second using $()
for f in $(ls Zoo_Animals*.sas |grep -vi Parrot |grep -vi Tiger); do echo $f; done
Edit: I think this has been answered successfully, but I can't check 'til later. I've reformatted it as suggested though.
The question: I have a series of files, each with a name of the form XXXXNAME, where XXXX is some number. I want to move them all to separate folders called XXXX and have them called NAME. I can do this manually, but I was hoping that by naming them XXXXNAME there'd be some way I could tell Terminal (I think that's the right name, but not really sure) to move them there. Something like
mv *NAME */NAME
but where it takes whatever * was in the first case and regurgitates it to the path.
This is on some form of Linux, with a bash shell.
In the real life case, the files are 0000GNUmakefile, with sequential numbering. I'm having to make lots of similar-but-slightly-altered versions of a program to compile and run on a cluster as part of my research. It would probably have been quicker to write a program to edit all the files and put in the right place in the first place, but I didn't.
This is probably extremely simple, and I should be able to find an answer myself, if I knew the right words. Thing is, I have no formal training in programming, so I don't know what to call things to search for them. So hopefully this will result in me getting an answer, and maybe knowing how to find out the answer for similar things myself next time. With the basic programming I've picked up, I'm sure I could write a program to do this for me, but I'm hoping there's a simple way to do it just using functionality already in Terminal. I probably shouldn't be allowed to play with these things.
Thanks for any help! I can actually program in C and Python a fair amount, but that's through trial and error largely, and I still don't know what I can do and can't do in Terminal.
SO many ways to achieve this.
I find that the old standbys sed and awk are often the most powerful.
ls | sed -rne 's:^([0-9]{4})(NAME)$:mv -iv & \1/\2:p'
If you're satisfied that the commands look right, pipe the command line through a shell:
ls | sed -rne 's:^([0-9]{4})(NAME)$:mv -iv & \1/\2:p' | sh
I put NAME in brackets and used \2 so that if it varies more than your example indicates, you can come up with a regular expression to handle your filenames better.
To do the same thing in gawk (GNU awk, the variant found in most GNU/Linux distros):
ls | gawk '/^[0-9]{4}NAME$/ {printf("mv -iv %s %s/%s\n", $1, substr($0,0,4), substr($0,5))}'
As with the first sample, this produces commands which, if they make sense to you, can be piped through a shell by appending | sh to the end of the line.
Note that with all these mv commands, I've added the -i and -v options. This is for your protection. Read the man page for mv (by typing man mv in your Linux terminal) to see if you should be comfortable leaving them out.
Also, I'm assuming with these lines that all your directories already exist. You didn't mention if they do. If they don't, here's a one-liner to create the directories.
ls | sed -rne 's:^([0-9]{4})(NAME)$:mkdir -p \1:p' | sort -u
As with the others, append | sh to run the commands.
I should mention that it is generally recommended to use constructs like for (in Tim's answer) or find instead of parsing the output of ls. That said, when your filename format is as simple as /[0-9]{4}word/, I find the quick sed one-liner to be the way to go.
Lastly, if by NAME you actually mean "any string of characters" rather than the literal string "NAME", then in all my examples above, replace NAME with .*.
The following script will do this for you. Copy the script into a file on the remote machine (we'll call it sortfiles.sh).
#!/bin/bash
# Get all files in current directory having names XXXXsomename, where X is an integer
files=$(find . -name '[0-9][0-9][0-9][0-9]*')
# Build a list of the XXXX patterns found in the list of files
dirs=
for name in ${files}; do
dirs="${dirs} $(echo ${name} | cut -c 3-6)"
done
# Remove redundant entries from the list of XXXX patterns
dirs=$(echo ${dirs} | uniq)
# Create any XXXX directories that are not already present
for name in ${dirs}; do
if [[ ! -d ${name} ]]; then
mkdir ${name}
fi
done
# Move each of the XXXXsomename files to the appropriate directory
for name in ${files}; do
mv ${name} $(echo ${name} | cut -c 3-6)
done
# Return from script with normal status
exit 0
From the command line, do chmod +x sortfiles.sh
Execute the script with ./sortfiles.sh
Just open the Terminal application, cd into the directory that contains the files you want moved/renamed, and copy and paste these commands into the command line.
for file in [0-9][0-9][0-9][0-9]*; do
dirName="${file%%*([^0-9])}"
mkdir -p "$dirName"
mv "$file" "$dirName/${file##*([0-9])}"
done
This assumes all the files that you want to rename and move are in the same directory. The file globbing also assumes that there are at least four digits at the start of the filename. If there are more than four numbers, it will still be caught, but not if there are less than four. If there are less than four, take off the appropriate number of [0-9]s from the first line.
It does not handle the case where "NAME" (i.e. the name of the new file you want) starts with a number.
See this site for more information about string manipulation in bash.
My program gets executed like:
$./sort 1 < test.txt
sort is the program name
1 is the argument (argv[1])
and test.txt is the file I am inputting from
Is it possible to extract the name file from this? if so how?
The problem is I already wrote my whole program as if I could extract the name from the input line, so I need to be able to pass it into arguments.
Any help is appreciated,
Thanks!
You can't. The shell opens (open(2)) that file and sets up the redirect (most likely using dup2).
The only possible way would be for the shell to explicitly export the information in an environment variable that you could read via getenv.
But it doesn't always make sense. For example, what file name would you expect from
$ echo "This is the end" | ./sort 1
Though this can't be done portably, it's possible on Linux by calling readlink on /proc/self/fd/0 (or /proc/some_pid/fd/0).
eg, running:
echo $(readlink /proc/self/fd/0 < /dev/null)
outputs:
/dev/null
No you can't: the shell sends the content of test.txt to the standard input of your program.
Look at this:
sort << _EOF
3
1
2
_EOF
The < > | operators are processed by the shell, they alter standard input,output,error of the programs in the cmd line.
If you happen to run Solaris, you could parse pfiles output to get the file associated, if any, with stdin.
$ /usr/bin/sleep 3600 < /tmp/foo &
[1] 8430
$ pfiles 8430
8430: /usr/bin/sleep 3600
Current rlimit: 65536 file descriptors
0: S_IFREG mode:0600 dev:299,2 ino:36867886 uid:12345 gid:67890 size=123
O_RDONLY|O_LARGEFILE
/tmp/foo
1: S_IFCHR mode:0600 dev:295,0 ino:12569206 uid:12345 gid:67890 rdev:24,2
...
On most Unix platforms, you will also get the same information from lsof -p if this freeware is installed.
I want to write a program that monitors syslog and performs an action when PPP authentication fails.
I think "tail -f /var/log/syslog" could help, but I'm not sure how to use it... probably using pipes?
I have found something similar written in bash, but I'm not sure how to implement it in C.
This is the bash method:
First create a named pipe using mkfifo:
$ mkfifo -p /home/mezgani/syslog.pipe
Make syslog.conf to points to this file:
*.info |/home/mezgani/syslog.pipe
Restart syslog:
$ sudo pkill -HUP syslogd
Create processing script that read the pipe
$ cat > foo
#!/bin/bash
cat /home/mezgani/syslog.pipe | while read input
do
# some stuff
echo ${input}
# ….
done
Finally I could found the solution!!
The solution was using named pipes!
First, I need to create a named pipe:
mkfifo /pipe
Then, I feed the pipe with the log info:
tail -f /var/log/syslog > /pipe
And then, I read the pipe from the C program using OPEN
int pipefd;
pipefd = open("/tmp/myFIFO", O_WRONLY);
Try to use inotify function. Using it you can monitor if a file or directory has changed.
I just got knocked down after our server has been updated from Debian 4 to 5.
We switched to UTF-8 environment and now we have problems getting the text printed correctly on the browser, because all files are in non-utf8 encodings like iso-8859-1, ascii, etc.
I tried many different scripts.
The first one I tried is "iconv". That one doesn't work, it changes the content, but the file's encoding is still non-utf8.
Same problem with enca, encamv, convmv and some other tools I installed via apt-get.
Then I found a python code, which uses chardet Universal Detector module, to detect encoding of a file (which works fine), but using the unicode class or the codec class to save it as utf-8 doesn't work, without any errors.
The only way I found to get the file and its content converted to UTF-8, is vi.
These are the steps I do for one file:
vi filename.php
:set bomb
:set fileencoding=utf-8
:wq
That's it. That one works perfect. But how can I get this running via a script?
I would like to write a script (Linux shell) which traverses a directory taking all php files, then converting them using vi with the commands above.
As I need to start the vi app, I do not know how to do something like this:
"vi --run-command=':set bomb, :set fileencoding=utf-8' filename.php"
Hope someone can help me.
This is the simplest way I know of to do this easily from the command line:
vim +"argdo se bomb | se fileencoding=utf-8 | w" $(find . -type f -name *.php)
Or better yet if the number of files is expected to be pretty large:
find . -type f -name *.php | xargs vim +"argdo se bomb | se fileencoding=utf-8 | w"
You could put your commands in a file, let's call it script.vim:
set bomb
set fileencoding=utf-8
wq
Then you invoke Vim with the -S (source) option to execute the script on the file you wish to fix. To do this on a bunch of files you could do
find . -type f -name "*.php" -exec vim -S script.vim {} \;
You could also put the Vim commands on the command line using the + option, but I think it may be more readable like this.
Note: I have not tested this.
You may actually want set nobomb (BOM = byte order mark), especially in the [not windows] world.
e.g., I had a script that didn't work as there was a byte order mark at the start. It isn't usually displayed in editors (even with set list in vi), or on the console, so its difficult to spot.
The file looked like this
#!/usr/bin/perl
...
But trying to run it, I get
./filename
./filename: line 1: #!/usr/bin/perl: No such file or directory
Not displayed, but at the start of the file, is the 3 byte BOM. So, as far as linux is concerned, the file doesn't start with #!
The solution is
vi filename
:set nobomb
:set fileencoding=utf-8
:wq
This removes the BOM at the start of the file, making it correct utf8.
NB Windows uses the BOM to identify a text file as being utf8, rather than ANSI. Linux (and the official spec) doesn't.
The accepted answer will keep the last file open in Vim. This problem can be easily resolved using the -c option of Vim,
vim +"argdo set bomb | set fileencoding=utf-8 | w" -c ":q" file1.txt file2.txt
If you need only process one file, the following will also work,
vim -c ':set bomb' -c ':set fileencoding=utf-8' -c ':wq' file1.txt