Hi. Im using cat to output the contents of a file, then piping it to my while read loop.In this loop variables get assigned values. However when i try to use the variables outside the loop their values has been reset.I understand about subshells etc. but I have no idea how to "preserve" the... (3 Replies)
Hi,
I did not understand why the following did not work out as I expected:
find . -name "pqp.txt" | grep -v "Permission"
I thought I would be able to catch whichever paths containing my pqp.txt file without receiving the display of messages such as "find: cannot access... Permisson... (1 Reply)
Hi,
I was wondering why ls * | echo does not print the contents of the directory to the screen? The way I see it, ls * returns a whole lot of information, and then we pipe all this info to echo, so surely it should all come to our screen!
Is there a serious flaw in my understanding?
... (3 Replies)
Not sure why this does not work in bash:
tail -f err.log |&
-bash: syntax error near unexpected token `&'
I am attempting to continuously read a file that is being updated by doing a "tail -f" on the file and piping the output to stdin which can then be read by the next shell command
Thnx (4 Replies)
Hi.
I have a script like so:
#!/bin/bash
download='php /var/www/last.php'
echo $download
if $downloadHow do I pipe the output of the php file into a variable, as when i run the if statement, it just echos the file output to the screen and does not actually consider the output (it will be... (2 Replies)
Hi All,
I am trying to convert the below Csh code into Perl.
But i have the following error.
Can any expert help ?
Error:
ls: *tac: No such file or directory
Csh
set $ST_file = `ls -rt *$testid*st*|tail -1`;
Perl
my $ST_file = `ls -rt *$testid*st*|tail -1`; (10 Replies)
I would like to pipe "top -n" to a text file, but I get an error:
top: cannot open /dev/kmem
kvm_open: Permission denied
I am a non-root user.
If I could find a way to get this type of output:
"Memory: 2048M real, 1516M free, 4099M swap free"
into a text file, I could further automate... (13 Replies)
Ok, so there is a perl script that runs as a server, on my local host. It tells me which port to use. I want to pipe that output into my browser so I can do the whole thing with a single command. The problem is, I think, that the program doesn't actually exit cause it's running a server, so...... (6 Replies)
Basically I was wondering if any of you know how to pipe the output of ls to a text file? so in my shell script one of the lines is ls but i want to pipe it into a file called directory listing.
Cheers.
I have tried ls | Directorylisting.txt
but it keeps saying " line 7: DirectoryListing.txt:... (9 Replies)
i have a file seperated each line seperated by newline. For example
alpha
beta
gamma
i am trying to replace the newlines to "," but dont want , present at the end of the line so i am trying the below one liner . but not sure whats wrong but its not working
cat myfile | tr -s '\n' ',' | sed... (9 Replies)
Discussion started by: chidori
9 Replies
LEARN ABOUT BSD
at
AT(1) General Commands Manual AT(1)NAME
at - execute commands at a later time
SYNOPSIS
at [ -c ] [ -s ] [ -m ] time [ day ] [ file ]
DESCRIPTION
At spools away a copy of the named file to be used as input to sh(1) or csh(1). If the -c flag (for (csh(1))) or the -s flag (for (sh(1)))
is specified, then that shell will be used to execute the job; if no shell is specified, the current environment shell is used. If no file
name is specified, at prompts for commands from standard input until a ^D is typed.
If the -m flag is specified, mail will be sent to the user after the job has been run. If errors occur during execution of the job, then a
copy of the error diagnostics will be sent to the user. If no errors occur, then a short message is sent informing the user that no errors
occurred.
The format of the spool file is as follows: A four line header that includes the owner of the job, the name of the job, the shell used to
run the job, and whether mail will be set after the job is executed. The header is followed by a cd command to the current directory and a
umask command to set the modes on any files created by the job. Then at copies all relevant environment variables to the spool file. When
the script is run, it uses the user and group ID of the creator of the spool file.
The time is 1 to 4 digits, with an optional following `A', `P', `N' or `M' for AM, PM, noon or midnight. One and two digit numbers are
taken to be hours, three and four digits to be hours and minutes. If no letters follow the digits, a 24 hour clock time is understood.
The optional day is either (1) a month name followed by a day number, or (2) a day of the week; if the word `week' follows, invocation is
moved seven days further off. Names of months and days may be recognizably truncated. Examples of legitimate commands are
at 8am jan 24
at -c -m 1530 fr week
at -s -m 1200n week
At programs are executed by periodic execution of the command /usr/libexec/atrun from cron(8). The granularity of at depends upon the how
often atrun is executed.
Error output is lost unless redirected or the -m flag is requested, in which case a copy of the errors is sent to the user via mail(1).
FILES
/usr/spool/at spooling area
/usr/spool/at/yy.ddd.hhhh.* job file
/usr/spool/at/past directory where jobs are executed from
/usr/spool/at/lasttimedone last time atrun was run
/usr/libexec/atrun executor (run by cron(8))
SEE ALSO atq(1), atrm(1), calendar(1), sleep(1), cron(8)DIAGNOSTICS
Complains about various syntax errors and times out of range.
BUGS
Due to the granularity of the execution of /usr/libexec/atrun, there may be bugs in scheduling things almost exactly 24 hours into the
future.
If the system crashes, mail is not sent to the user informing them that the job was not completed.
Sometimes old spool files are not removed from the directory /usr/spool/at/past. This is usually due to a system crash, and requires that
they be removed by hand.
4th Berkeley Distribution October 21, 1996 AT(1)