How to pipe awk output (with periodic, continuous input) to output file?
I am trying to write a command that pipes the continuous output of a free command (run every second) to an awk command that parses a specific value (available free memory) and outputs this to a file with a timestamp. Here are my current attempts at the command:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 }' >>memOut
And alternatively, after a bit of Googling
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 >>"memOut"}'
Each run produces empty files. Any suggestions or possibly different methods?
awk pipe
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
asked Jan 16 '12 at 19:19
Mark
255127
add a comment |
I am trying to write a command that pipes the continuous output of a free command (run every second) to an awk command that parses a specific value (available free memory) and outputs this to a file with a timestamp. Here are my current attempts at the command:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 }' >>memOut
And alternatively, after a bit of Googling
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 >>"memOut"}'
Each run produces empty files. Any suggestions or possibly different methods?
awk pipe
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
asked Jan 16 '12 at 19:19
Mark
255127
add a comment |
I am trying to write a command that pipes the continuous output of a free command (run every second) to an awk command that parses a specific value (available free memory) and outputs this to a file with a timestamp. Here are my current attempts at the command:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 }' >>memOut
And alternatively, after a bit of Googling
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 >>"memOut"}'
Each run produces empty files. Any suggestions or possibly different methods?
awk pipe
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
asked Jan 16 '12 at 19:19
Mark
255127
I am trying to write a command that pipes the continuous output of a free command (run every second) to an awk command that parses a specific value (available free memory) and outputs this to a file with a timestamp. Here are my current attempts at the command:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 }' >>memOut
And alternatively, after a bit of Googling
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4 >>"memOut"}'
Each run produces empty files. Any suggestions or possibly different methods?
awk pipe
awk pipe
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
asked Jan 16 '12 at 19:19
Mark
255127
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
asked Jan 16 '12 at 19:19
Mark
255127
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
edited Jul 14 '14 at 17:04
Cfinley
1,43331120
1,43331120
asked Jan 16 '12 at 19:19
Mark
255127
asked Jan 16 '12 at 19:19
Mark
255127
asked Jan 16 '12 at 19:19
Mark
255127
255127
add a comment |
add a comment |
4 Answers
4
active
oldest
votes
You have to flush the buffer to see something in memOut during the execution:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Here's an alternative version:
while sleep 1; do sed -n "s/MemFree: */`date`, /p" /proc/meminfo; done >> memOut
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
add a comment |
For old versions of awk you may have to use system("").
Actually, fflush(stdout) is for only for recent versions of awk and gawk, as its only in the POSIX standard since December 2012.
free -mto -s 1 | awk '/Mem/ {
print strftime("%r") "," $4;
system(""); # Flush output
}' >> memOut
Note that using system("") flushes every file descriptor, its full description is in the gawk manual, section "9.1.4 Input/Output Functions".
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
add a comment |
Just to make sure that you are getting what you actually want and not what you specifically asked.
If you want to know available memory on the system for programs then this might be more suitable:
free -m -s 1 | awk '/buffers/cache/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Mem line's Used column includes caches and buffers and in most cases when you want to monitor memory usage for given computer/task those should at least be noted.
answered Jan 16 '12 at 22:01
Manwe
868412
add a comment |
On certain versions of awk (e.g. mawk 1.3.3) you need to add the -W interactive command line flag to enable unbuffered operation with pipes.
answered Dec 15 at 15:50
Pierz
58058
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
You have to flush the buffer to see something in memOut during the execution:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Here's an alternative version:
while sleep 1; do sed -n "s/MemFree: */`date`, /p" /proc/meminfo; done >> memOut
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
add a comment |
You have to flush the buffer to see something in memOut during the execution:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Here's an alternative version:
while sleep 1; do sed -n "s/MemFree: */`date`, /p" /proc/meminfo; done >> memOut
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
add a comment |
You have to flush the buffer to see something in memOut during the execution:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Here's an alternative version:
while sleep 1; do sed -n "s/MemFree: */`date`, /p" /proc/meminfo; done >> memOut
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
You have to flush the buffer to see something in memOut during the execution:
free -mto -s 1 | awk '/Mem/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Here's an alternative version:
while sleep 1; do sed -n "s/MemFree: */`date`, /p" /proc/meminfo; done >> memOut
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
edited Jan 16 '12 at 20:00
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
answered Jan 16 '12 at 19:48
cYrus
15.7k55168
15.7k55168
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
add a comment |
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
This gave me the output file I wanted. Thank you!
– Mark
Jan 16 '12 at 19:54
add a comment |
For old versions of awk you may have to use system("").
Actually, fflush(stdout) is for only for recent versions of awk and gawk, as its only in the POSIX standard since December 2012.
free -mto -s 1 | awk '/Mem/ {
print strftime("%r") "," $4;
system(""); # Flush output
}' >> memOut
Note that using system("") flushes every file descriptor, its full description is in the gawk manual, section "9.1.4 Input/Output Functions".
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
add a comment |
For old versions of awk you may have to use system("").
Actually, fflush(stdout) is for only for recent versions of awk and gawk, as its only in the POSIX standard since December 2012.
free -mto -s 1 | awk '/Mem/ {
print strftime("%r") "," $4;
system(""); # Flush output
}' >> memOut
Note that using system("") flushes every file descriptor, its full description is in the gawk manual, section "9.1.4 Input/Output Functions".
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
add a comment |
For old versions of awk you may have to use system("").
Actually, fflush(stdout) is for only for recent versions of awk and gawk, as its only in the POSIX standard since December 2012.
free -mto -s 1 | awk '/Mem/ {
print strftime("%r") "," $4;
system(""); # Flush output
}' >> memOut
Note that using system("") flushes every file descriptor, its full description is in the gawk manual, section "9.1.4 Input/Output Functions".
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
For old versions of awk you may have to use system("").
Actually, fflush(stdout) is for only for recent versions of awk and gawk, as its only in the POSIX standard since December 2012.
free -mto -s 1 | awk '/Mem/ {
print strftime("%r") "," $4;
system(""); # Flush output
}' >> memOut
Note that using system("") flushes every file descriptor, its full description is in the gawk manual, section "9.1.4 Input/Output Functions".
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
answered Feb 4 '13 at 10:29
Steve Schnepp
3211510
3211510
add a comment |
add a comment |
Just to make sure that you are getting what you actually want and not what you specifically asked.
If you want to know available memory on the system for programs then this might be more suitable:
free -m -s 1 | awk '/buffers/cache/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Mem line's Used column includes caches and buffers and in most cases when you want to monitor memory usage for given computer/task those should at least be noted.
answered Jan 16 '12 at 22:01
Manwe
868412
add a comment |
Just to make sure that you are getting what you actually want and not what you specifically asked.
If you want to know available memory on the system for programs then this might be more suitable:
free -m -s 1 | awk '/buffers/cache/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Mem line's Used column includes caches and buffers and in most cases when you want to monitor memory usage for given computer/task those should at least be noted.
answered Jan 16 '12 at 22:01
Manwe
868412
add a comment |
Just to make sure that you are getting what you actually want and not what you specifically asked.
If you want to know available memory on the system for programs then this might be more suitable:
free -m -s 1 | awk '/buffers/cache/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Mem line's Used column includes caches and buffers and in most cases when you want to monitor memory usage for given computer/task those should at least be noted.
answered Jan 16 '12 at 22:01
Manwe
868412
Just to make sure that you are getting what you actually want and not what you specifically asked.
If you want to know available memory on the system for programs then this might be more suitable:
free -m -s 1 | awk '/buffers/cache/ { print strftime("%r") "," $4; fflush(stdout) }' >> memOut
Mem line's Used column includes caches and buffers and in most cases when you want to monitor memory usage for given computer/task those should at least be noted.
answered Jan 16 '12 at 22:01
Manwe
868412
answered Jan 16 '12 at 22:01
Manwe
868412
answered Jan 16 '12 at 22:01
Manwe
868412
answered Jan 16 '12 at 22:01
Manwe
868412
868412
add a comment |
add a comment |
On certain versions of awk (e.g. mawk 1.3.3) you need to add the -W interactive command line flag to enable unbuffered operation with pipes.
answered Dec 15 at 15:50
Pierz
58058
add a comment |
On certain versions of awk (e.g. mawk 1.3.3) you need to add the -W interactive command line flag to enable unbuffered operation with pipes.
answered Dec 15 at 15:50
Pierz
58058
add a comment |
On certain versions of awk (e.g. mawk 1.3.3) you need to add the -W interactive command line flag to enable unbuffered operation with pipes.
answered Dec 15 at 15:50
Pierz
58058
On certain versions of awk (e.g. mawk 1.3.3) you need to add the -W interactive command line flag to enable unbuffered operation with pipes.
answered Dec 15 at 15:50
Pierz
58058
answered Dec 15 at 15:50
Pierz
58058
answered Dec 15 at 15:50
Pierz
58058
answered Dec 15 at 15:50
Pierz
58058
58058
add a comment |
add a comment |
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