Is there an option, for cat, head, tail, or is there any way, to display a file from last line to first? For example, my file
looks like this:
aaaa
bbbb
cccc
eeee
and I would like to print or display it like this:
eeee
cccc
bbbb
aaaa
thanks (5 Replies)
Hi, excuse me for my poor english.
My problem is that:
I have a File
i want to add to each line of that file two strings: one at the beginning of the line, one at the ending.
string1="abcd"
string2="efgh"
i want $string1 content $string2 for each line.
Is that possible? (3 Replies)
Hello -
I am running Linux. I want to place a comment char at the beginning of a line in a file. For example:
testvar=`grep username /etc/people
sed -e 's/$testvar/#$testvar/g' /etc/people
I cannot get the above commands to put a comment at the beginning of the line.
Any... (3 Replies)
Hello,
I have a file as follow
a
b
c
c
d
d
e
I would like to write a awk command to insert # from the first occurence of
"c" to the end of the files.
OUTPUT should be like this
a
b
#c (5 Replies)
How can I specify special meaning characters like ^ or $ inside a regex range. e.g
Suppose I want to search for a string that either starts with '|' character or begins with start-of-line character.
I tried the following but it does not work:
sed 's/\(\)/<do something here>/g' file1
... (3 Replies)
Well here goes:
I tried to write a batch file that adds a specific fixed text to each line of an already existing text file.
for the adding text infront of each line I tried this:
for /F "delims=" %%j in (list.txt) do echo.STARTTEXT\%%j >> list.txt
for adding text after each line I... (0 Replies)
How would you do vim copy line and paste at the beginning, middle, and end of another line. I know yy copies the whole line and p pastes the whole line, but on its own separate line. Sometimes I would like to copy a line to the beginning, middle, or end of another line. I would think this would be... (3 Replies)
I need to comment the lines starting with pattern "exclude" or "exclude=". If the work exclude comes at any other part, ignore it. Also, ignore, excludes, excluded etc. Ie only comment the line starting with exclude.
File contents.
exclude
exclude=
hi I am excluded
excludes
excludes=
... (9 Replies)
Hi,
I have a specific requirement to add text at the beginning and end of a plain text file. I tried to use "sed" with '1i' and '$a' flags but these required two separate "sed" commands separated with "|".
I am looking for some command/option to join these two in single command parameter.
... (6 Replies)
Discussion started by: bhupinder08
6 Replies
LEARN ABOUT LINUX
unbuffer
UNBUFFER(1) General Commands Manual UNBUFFER(1)NAME
unbuffer - unbuffer output
SYNOPSIS
unbuffer program [ args ]
INTRODUCTION
unbuffer disables the output buffering that occurs when program output is redirected from non-interactive programs. For example, suppose
you are watching the output from a fifo by running it through od and then more.
od -c /tmp/fifo | more
You will not see anything until a full page of output has been produced.
You can disable this automatic buffering as follows:
unbuffer od -c /tmp/fifo | more
Normally, unbuffer does not read from stdin. This simplifies use of unbuffer in some situations. To use unbuffer in a pipeline, use the
-p flag. Example:
process1 | unbuffer -p process2 | process3
CAVEATS
unbuffer -p may appear to work incorrectly if a process feeding input to unbuffer exits. Consider:
process1 | unbuffer -p process2 | process3
If process1 exits, process2 may not yet have finished. It is impossible for unbuffer to know long to wait for process2 and process2 may
not ever finish, for example, if it is a filter. For expediency, unbuffer simply exits when it encounters an EOF from either its input or
process2.
In order to have a version of unbuffer that worked in all situations, an oracle would be necessary. If you want an application-specific
solution, workarounds or hand-coded Expect may be more suitable. For example, the following example shows how to allow grep to finish pro-
cessing when the cat before it finishes first. Using cat to feed grep would never require unbuffer in real life. It is merely a place-
holder for some imaginary process that may or may not finish. Similarly, the final cat at the end of the pipeline is also a placeholder
for another process.
$ cat /tmp/abcdef.log | grep abc | cat
abcdef
xxxabc defxxx
$ cat /tmp/abcdef.log | unbuffer grep abc | cat
$ (cat /tmp/abcdef.log ; sleep 1) | unbuffer grep abc | cat
abcdef
xxxabc defxxx
$
BUGS
The man page is longer than the program.
SEE ALSO
"Exploring Expect: A Tcl-Based Toolkit for Automating Interactive Programs" by Don Libes, O'Reilly and Associates, January 1995.
AUTHOR
Don Libes, National Institute of Standards and Technology
1 June 1994 UNBUFFER(1)