Log date and time accurately with batch file
I have a batch file that backups my files and works nicely, however I wanted to be able to log the exact time each task starts, but it is not working as I expected.
@echo off
> C:log%date:~3,2%-%date:~0,2%.log (
echo %time% - Backing up first part
... some logic
echo %time% - Backing up second part
...
)
The problem is that I get the exact same time for both instances of %time%, instead of displaying the exact time as I wanted.
I assume it has something to do with delayed expansion, maybe DOS assigns a value to time the first time around and keeps that value througout the whole file.
What should I do to be able to reflect the time at which the echo is actually called?
windows batch ms-dos
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
add a comment |
I have a batch file that backups my files and works nicely, however I wanted to be able to log the exact time each task starts, but it is not working as I expected.
@echo off
> C:log%date:~3,2%-%date:~0,2%.log (
echo %time% - Backing up first part
... some logic
echo %time% - Backing up second part
...
)
The problem is that I get the exact same time for both instances of %time%, instead of displaying the exact time as I wanted.
I assume it has something to do with delayed expansion, maybe DOS assigns a value to time the first time around and keeps that value througout the whole file.
What should I do to be able to reflect the time at which the echo is actually called?
windows batch ms-dos
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
add a comment |
I have a batch file that backups my files and works nicely, however I wanted to be able to log the exact time each task starts, but it is not working as I expected.
@echo off
> C:log%date:~3,2%-%date:~0,2%.log (
echo %time% - Backing up first part
... some logic
echo %time% - Backing up second part
...
)
The problem is that I get the exact same time for both instances of %time%, instead of displaying the exact time as I wanted.
I assume it has something to do with delayed expansion, maybe DOS assigns a value to time the first time around and keeps that value througout the whole file.
What should I do to be able to reflect the time at which the echo is actually called?
windows batch ms-dos
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
I have a batch file that backups my files and works nicely, however I wanted to be able to log the exact time each task starts, but it is not working as I expected.
@echo off
> C:log%date:~3,2%-%date:~0,2%.log (
echo %time% - Backing up first part
... some logic
echo %time% - Backing up second part
...
)
The problem is that I get the exact same time for both instances of %time%, instead of displaying the exact time as I wanted.
I assume it has something to do with delayed expansion, maybe DOS assigns a value to time the first time around and keeps that value througout the whole file.
What should I do to be able to reflect the time at which the echo is actually called?
windows batch ms-dos
windows batch ms-dos
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
asked Jan 28 at 15:33
Luis Esparza LeedMxLuis Esparza LeedMx
478
478
add a comment |
add a comment |
1 Answer
1
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oldest
votes
Classic delayed expansion issue.
Your problem is that %time% expansion occurs when the statement is parsed, and the entire parenthesized block is parsed at the same time, before any commands are executed.
There are three possible solutions:
1) Use TIME /T instead
This avoids the whole issue of expansion timing. But the format is different, and there is a newline after the time, so you can't add a label to the end.
time /t
echo Backing up first part
If you want the label on the same line, then you could reverse the order and use SET /P
<nul set /p "Backing up first part - "
time /t
Or you can capture the output with a FOR /F loop and put everything on one line
for /f "delims=" %%T in ('time /t') do echo %%T - Backing up first part:
2) Use CALL and doubled percents to get an extra round of parsing
call echo %%time%% - Backing up first part:
See How does the Windows Command Interpreter (CMD.EXE) parse scripts? for an understanding of why this works. Phases 1 and 6 are relevant here. But be forewarned - it is a lot of very dense material that will take time to digest.
3) Use delayed expansion
This is the technique that I prefer to use.
This is much faster than the CALL hack. It requires SETLOCAL to enable delayed expansion, and use of ! instead of % to expand the variable:
setlocal enableDelayedExpansion
> C:log%date:~3,2%-%date:~0,2%.log (
echo !time! - Backing up first part
... some logic
echo !time! - Backing up second part
...
)
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
add a comment |
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1 Answer
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active
oldest
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1 Answer
1
active
oldest
votes
active
oldest
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active
oldest
votes
Classic delayed expansion issue.
Your problem is that %time% expansion occurs when the statement is parsed, and the entire parenthesized block is parsed at the same time, before any commands are executed.
There are three possible solutions:
1) Use TIME /T instead
This avoids the whole issue of expansion timing. But the format is different, and there is a newline after the time, so you can't add a label to the end.
time /t
echo Backing up first part
If you want the label on the same line, then you could reverse the order and use SET /P
<nul set /p "Backing up first part - "
time /t
Or you can capture the output with a FOR /F loop and put everything on one line
for /f "delims=" %%T in ('time /t') do echo %%T - Backing up first part:
2) Use CALL and doubled percents to get an extra round of parsing
call echo %%time%% - Backing up first part:
See How does the Windows Command Interpreter (CMD.EXE) parse scripts? for an understanding of why this works. Phases 1 and 6 are relevant here. But be forewarned - it is a lot of very dense material that will take time to digest.
3) Use delayed expansion
This is the technique that I prefer to use.
This is much faster than the CALL hack. It requires SETLOCAL to enable delayed expansion, and use of ! instead of % to expand the variable:
setlocal enableDelayedExpansion
> C:log%date:~3,2%-%date:~0,2%.log (
echo !time! - Backing up first part
... some logic
echo !time! - Backing up second part
...
)
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
add a comment |
Classic delayed expansion issue.
Your problem is that %time% expansion occurs when the statement is parsed, and the entire parenthesized block is parsed at the same time, before any commands are executed.
There are three possible solutions:
1) Use TIME /T instead
This avoids the whole issue of expansion timing. But the format is different, and there is a newline after the time, so you can't add a label to the end.
time /t
echo Backing up first part
If you want the label on the same line, then you could reverse the order and use SET /P
<nul set /p "Backing up first part - "
time /t
Or you can capture the output with a FOR /F loop and put everything on one line
for /f "delims=" %%T in ('time /t') do echo %%T - Backing up first part:
2) Use CALL and doubled percents to get an extra round of parsing
call echo %%time%% - Backing up first part:
See How does the Windows Command Interpreter (CMD.EXE) parse scripts? for an understanding of why this works. Phases 1 and 6 are relevant here. But be forewarned - it is a lot of very dense material that will take time to digest.
3) Use delayed expansion
This is the technique that I prefer to use.
This is much faster than the CALL hack. It requires SETLOCAL to enable delayed expansion, and use of ! instead of % to expand the variable:
setlocal enableDelayedExpansion
> C:log%date:~3,2%-%date:~0,2%.log (
echo !time! - Backing up first part
... some logic
echo !time! - Backing up second part
...
)
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
add a comment |
Classic delayed expansion issue.
Your problem is that %time% expansion occurs when the statement is parsed, and the entire parenthesized block is parsed at the same time, before any commands are executed.
There are three possible solutions:
1) Use TIME /T instead
This avoids the whole issue of expansion timing. But the format is different, and there is a newline after the time, so you can't add a label to the end.
time /t
echo Backing up first part
If you want the label on the same line, then you could reverse the order and use SET /P
<nul set /p "Backing up first part - "
time /t
Or you can capture the output with a FOR /F loop and put everything on one line
for /f "delims=" %%T in ('time /t') do echo %%T - Backing up first part:
2) Use CALL and doubled percents to get an extra round of parsing
call echo %%time%% - Backing up first part:
See How does the Windows Command Interpreter (CMD.EXE) parse scripts? for an understanding of why this works. Phases 1 and 6 are relevant here. But be forewarned - it is a lot of very dense material that will take time to digest.
3) Use delayed expansion
This is the technique that I prefer to use.
This is much faster than the CALL hack. It requires SETLOCAL to enable delayed expansion, and use of ! instead of % to expand the variable:
setlocal enableDelayedExpansion
> C:log%date:~3,2%-%date:~0,2%.log (
echo !time! - Backing up first part
... some logic
echo !time! - Backing up second part
...
)
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
Classic delayed expansion issue.
Your problem is that %time% expansion occurs when the statement is parsed, and the entire parenthesized block is parsed at the same time, before any commands are executed.
There are three possible solutions:
1) Use TIME /T instead
This avoids the whole issue of expansion timing. But the format is different, and there is a newline after the time, so you can't add a label to the end.
time /t
echo Backing up first part
If you want the label on the same line, then you could reverse the order and use SET /P
<nul set /p "Backing up first part - "
time /t
Or you can capture the output with a FOR /F loop and put everything on one line
for /f "delims=" %%T in ('time /t') do echo %%T - Backing up first part:
2) Use CALL and doubled percents to get an extra round of parsing
call echo %%time%% - Backing up first part:
See How does the Windows Command Interpreter (CMD.EXE) parse scripts? for an understanding of why this works. Phases 1 and 6 are relevant here. But be forewarned - it is a lot of very dense material that will take time to digest.
3) Use delayed expansion
This is the technique that I prefer to use.
This is much faster than the CALL hack. It requires SETLOCAL to enable delayed expansion, and use of ! instead of % to expand the variable:
setlocal enableDelayedExpansion
> C:log%date:~3,2%-%date:~0,2%.log (
echo !time! - Backing up first part
... some logic
echo !time! - Backing up second part
...
)
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
answered Jan 28 at 16:21
dbenhamdbenham
7,91142030
7,91142030
add a comment |
add a comment |
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