02-16-2011
You just have to wait for the buffer to be filed ...,
or use --line-buffered, if your grep implementation supports this (or a similar) option.
The stdout is buffered, when passed through a pipe.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
I am somewhat of a novice at unix scripting and I need a little help. Here is what im trying to do:
I am trying to figure out how to pipe the following grep results into a file.
/source/programs: grep "WSBL020" W*
WBMB991.cbl: COPY WSBL020.
WDCB003.cbl: COPY... (4 Replies)
Discussion started by: katinicsdad
4 Replies
2. Shell Programming and Scripting
hi,
How can I check for a field in a pipe-delimited file having a NULL value in Unix using a grep command or any other command.
Please reply (5 Replies)
Discussion started by: sureshg_sampat
5 Replies
3. UNIX Desktop Questions & Answers
OK... I'm fairly new to unix having the admin handed to me on a platter w/almost no training.
However, being a programmer, I do pick up things fairly easily, but this one is getting the best of me.
I have a unix server that runs multiple versions of the same ERP system, hand crafted for our... (1 Reply)
Discussion started by: chimodel
1 Replies
4. Shell Programming and Scripting
The program that is running on my machine generates log files. I want to be able to know the number of lines that contain "FT" in the most recent log file. I wrote the following, but it always returns zero. And I know the count is not zero. Any ideas?
ls -rt *.log | tail -n 1 | grep -c FT (6 Replies)
Discussion started by: sdilucca
6 Replies
5. Shell Programming and Scripting
I have some complication with this, I have a file like below for DEV_1 till DEV_10. and the db values are set accordinly which are not unique. For example DEV1,DEV4,DEV6 can have the same target DB name.
I waned to identify for DEV_2 and then replace the TARGET_DATABASE value with the new DB... (6 Replies)
Discussion started by: yesmani
6 Replies
6. Shell Programming and Scripting
hi,
i want to write in a file the output of one command and pile also the same output
like ls -lrt > some_file | wc -l (9 Replies)
Discussion started by: narang.mohit
9 Replies
7. UNIX for Advanced & Expert Users
The "write failed: Broken pipe" message is reported by the file sending PC which run my writed network device driver while 500MB or 900MB is sended!
What does the message mean? Does this mean there is a bug in my driver?
li,kunlun (11 Replies)
Discussion started by: liklstar
11 Replies
8. UNIX for Dummies Questions & Answers
I am using grep to match a pattern, but the output is strange.
$ grep -r -o "pattern" *
Gives me:
Binary file foo1 matches
Binary file foo2 matches
Binary file foo3 matches
To find the lines before/after, I then have to use the following on each file:
$ strings foo1 | grep -A1 -B1... (0 Replies)
Discussion started by: chipperuga
0 Replies
9. UNIX for Dummies Questions & Answers
Hello.
I want to get all modules which are loaded and which name are exactly 2 characters long and not more than 2 characters and begin with "nv"
lsmod | (e)grep '^nv????????????
I want to get all modules which are loaded and which name begin with "nv" and are 2 to 7 characters long
... (1 Reply)
Discussion started by: jcdole
1 Replies
10. Shell Programming and Scripting
So, this is weird... I'm running this command:
iotop -o -P -k -bt -d 5
I'd like to save the output relelvant to rsyslogd to a file, so I do this:
iotop -o -P -k -bt -d 5 | grep rsyslogd >> /var/log/rsyslogd
Nothing is written to the file! I can write the full output to the file:
... (2 Replies)
Discussion started by: treesloth
2 Replies
LEARN ABOUT OPENDARWIN
tail
TAIL(1) BSD General Commands Manual TAIL(1)
NAME
tail -- display the last part of a file
SYNOPSIS
tail [-F | -f | -r] [-b number | -c number | -n number] [file ...]
DESCRIPTION
The tail utility displays the contents of file or, by default, its standard input, to the standard output.
The display begins at a byte, line or 512-byte block location in the input. Numbers having a leading plus (``+'') sign are relative to the
beginning of the input, for example, ``-c +2'' starts the display at the second byte of the input. Numbers having a leading minus (``-'')
sign or no explicit sign are relative to the end of the input, for example, ``-n 2'' displays the last two lines of the input. The default
starting location is ``-n 10'', or the last 10 lines of the input.
The options are as follows:
-b number
The location is number 512-byte blocks.
-c number
The location is number bytes.
-f The -f option causes tail to not stop when end of file is reached, but rather to wait for additional data to be appended to the
input. The -f option is ignored if the standard input is a pipe, but not if it is a FIFO.
-F The -F option implies the -f option, but tail will also check to see if the file being followed has been renamed or rotated. The
file is closed and reopened when tail detects that the filename being read from has a new inode number. The -F option is ignored if
reading from standard input rather than a file.
-n number
The location is number lines.
-r The -r option causes the input to be displayed in reverse order, by line. Additionally, this option changes the meaning of the -b,
-c and -n options. When the -r option is specified, these options specify the number of bytes, lines or 512-byte blocks to display,
instead of the bytes, lines or blocks from the beginning or end of the input from which to begin the display. The default for the -r
option is to display all of the input.
If more than a single file is specified, each file is preceded by a header consisting of the string ``==> XXX <=='' where ``XXX'' is the name
of the file.
DIAGNOSTICS
The tail utility exits 0 on success, and >0 if an error occurs.
SEE ALSO
cat(1), head(1), sed(1)
STANDARDS
The tail utility is expected to be a superset of the IEEE Std 1003.2-1992 (``POSIX.2'') specification. In particular, the -F, -b and -r
options are extensions to that standard.
The historic command line syntax of tail is supported by this implementation. The only difference between this implementation and historic
versions of tail, once the command line syntax translation has been done, is that the -b, -c and -n options modify the -r option, i.e. ``-r
-c 4'' displays the last 4 characters of the last line of the input, while the historic tail (using the historic syntax ``-4cr'') would
ignore the -c option and display the last 4 lines of the input.
HISTORY
A tail command appeared in PWB UNIX.
BSD
June 6, 1993 BSD