I know how to send a file as input when running a command like this:
./foo < input.txt
but how can I run foo interactively, and then after a while redirect it's input? Something like this:
./foo
CTRL-Z
fg < input.txt
In Unix/Linux/etc you can do this:
cat /dev/tty input.txt | ./foo
Type Control-D (or whatever your EOF character is) to end the interactive part of the input.
Related
I'm using the below line perfectly fine on the console, but when i use it in a makefile i get the below error. I have tried different things for last hour, nothing helps me. Also i have to use '#' before the command in makefile, that is normal only. Any help is greatly welcome.
Command on console
cpio -itv < rootfs.cpio | awk '!/^d/{$8="";print}' | sort -k8 > rootfs.layout.trim
Error
awk: !/^d/{="";print}
awk: ^ syntax error
In makefile
log-rootfs:
# copy the layout dump with all the modification needed to sync with stb output
# get the file list from cpio file => remove the lines with directory name => sort the output and store the same in layout file
cpio -itv < $(ROOTFS_CPIO_FILE) | awk '!/^d/{$8="";print}' | sort -k8 > $(ROOTFS_LAYOUT)
#echo $(ROOTFS_LAYOUT) is created
make is looking for a variable/macro named $8. In general, $ needs to be escaped in the makefile, and if you want to pass a literal $ to the shell, you should use $$ in the makefile. In other words, try:
rule:
... awk '!/^d/{$$8="";print}' ...
I went through several grep examples, but don't see how to do the following.
Say, i have a file with a line
! some test here and number -123.2345 text
i can get this line using
grep ! input.txt
but how do i get the number (possibly positive or negative) from this line and append it to the end of another file? Is it possible to apply grep to grep results?
If yes, then i could get the number via something like
grep -Eo "[0-9]{1,}|\-[0-9]{1,}"
p/s/ i am using OS-X
p/p/s/ i'm trying to fetch data from several files and put into a single file for later plotting.
The format with your commands would be:
grep ! input.txt | grep -Eo "[0-9]{1,}|\-[0-9]{1,}" >> output
To grep from grep we use the pipe operator | this lets us chain commands together. To append this output to a file we use the redirection operator >>.
However there are a couple of problems. You regexp is better written: grep -Eoe '-?[0-9.]+' this allows for the decimal and returns the single number instead of two and if you want lines that start with ! then grep ^! is better to avoid matches with lines what contain ! but don't start with it. Better to do:
grep '^!' input | grep -Eoe '-?[0-9.]+' >> output
perl -lne 'm/.*?([\d\.\-]+).*/g;print $1' your_file >>anotherfile_to_append
$foo="! some test here and number -123.2345 text"
$echo $foo | sed -e 's/[^0-9\.-]//g'
$-123.2345
Edit:-
for a file,
[ ]$ cat log
! some test here and number -123.2345 text
some blankline
some line without "the character" and with number 345.566
! again a number 34
[ ]$ sed -e '/^[^!]/d' -e 's/[^0-9.-]//g' log > op
[ ]$ cat op
-123.2345
34
Now lets see the toothpicks :) '/^[^!]/d' / start of pattern, ^ not (like multiply with false), [^!] anyline starting with ! and d delete. Second expression, [^0-9.-] not matching anything within 0 to 9, and . and -, (everything else) // replace with nothing (i.e. delete) and done :)
I have a text source (a log file), which gets new lines appended to it by some third party.
I can output the additions to my source file using tail -f source. I can then pipe that through an awk script awk -f parser.awk to parse and format the output.
My question is: while tail -f source | awk -f parser.awk is running, is there a way to call function foo() inside my parser.awk script every time there is more than 5 seconds elapsed without anything coming through the pipe into the standard input of the awk script?
Edit: Currently using GNU Awk 3.1.6. May be able to upgrade to newer version if required.
If your shell's read supports -t and -u, here's an ugly hack:
{ echo hello; sleep 6; echo world; } | awk 'BEGIN{
while( "while read -t 5 -u 3 line; do echo \"$line\"; done" | getline > 0 )
print
}' 3<&0
You can replace the print in the body of the while loop with your script. However, it would probably make a lot more sense to put the read timeout between tail and awk in the pipeline, and it would make even more sense to re-implement tail to timeout.
Not exactly the answer to your question. However there is a little hack in shell that can do practically what you want:
{ tail -f log.file >&2 | { while : ; do sleep 5; echo SECRET_PHRASE ; done ; } ; } 2>&1 | awk -f script.awk
When awk receives SECRET_PHRASE it will run foo function every 5 seconds. Unfortunately is will run it every 5 second even in case there was some output during this time from tail.
ps. You can replace '{}' with '()' and vice versa. In the first case it won't create subshell, in the second one it will.
The another way is to append this secret phrase dirctly to log file in case nobody wrote there during last five seconds. But looks like it's not good idea due to you will have spoiled log file.
I'm writing a shell script and I need to strip FIND ME out of something like this:
* *[**FIND ME**](find me)*
and assign it to an array. I had the code working flawlessly .. until I moved the script in Solaris to a non-global zone. Here is the code I used before:
objectArray[$i]=`echo $line | nawk -F '*[**|**]' '{print $2}'`
Now Prints:
awk: syntax error near line 1
awk: bailing out near line 1
It was suggested that I try the same command with nawk, but I receive this error now instead:
nawk: illegal primary in regular expression `* *[**|**]` at `*[**|**]`
input record number 1
source line number 1
Also, /usr/xpg4/bin/awk does not exist.
I think you need to be clearer on what you want to get. For me your awk line doesn't 'strip FIND ME out'
echo "* *[**FIND ME**](find me)*" | nawk -F '* *[**|**]' '{print $2}'
[
So it would help if you gave some examples of the input/output you are expecting. Maybe there's a way to do what you want with sed?
EDIT:
From comments you actually want to select "FIND ME" from line, not strip it out.
I guess the dialect of regular expressions accepted by this nawk is different than gawk. So maybe a tool that's better suited to the job is in order.
echo "* *[**FIND ME**](find me)*" | sed -e"s/.*\* \*\[\*\*\(.[^*]*\)\*\*\].*/\1/"
FIND ME
quote your $line variable like this: "$line". If still doesn't work, you can do it another way with nawk, since you only want to find one instance of FIND ME,
$ echo "$line" | nawk '{gsub(/.*\*\[\*\*|\*\*\].*/,"");print}'
FIND ME
or if you are using bash/ksh on Solaris,
$ line="${line#*\[\*\*}"
$ echo "${line%%\*\*\]*}"
FIND ME
It just occur to me that following command can print output in text file.
./a.out < infile.txt > actualoutput.txt
But i still wondering what < infile.txt > is for?
And what other arguments i can give when executing this object file?
this is the file that will be used as the standard input ( aka stdin ).
Your command is the same as
cat infile.txt | a.out > output.txt
The < infile.txt means take standard input from infile.txt.
Similarly > actualoutput.txt means to send standard output to actualoutput.txt.
For more information on redirection take a look here.