Parsing the output of date with sed
up vote
1
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I am trying to replace the whitespaces in the output of date with '_' with no success.
$date
Fri Sep 14 14:10:04 EDT 2012
$ date | sed 's/ /_/'
Fri_Sep 14 14:10:24 EDT 2012
As you can see, the last command only replaced the first whitespace by a _'. Why did it skip the other whitespaces?
shell sed date
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
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up vote
1
down vote
favorite
I am trying to replace the whitespaces in the output of date with '_' with no success.
$date
Fri Sep 14 14:10:04 EDT 2012
$ date | sed 's/ /_/'
Fri_Sep 14 14:10:24 EDT 2012
As you can see, the last command only replaced the first whitespace by a _'. Why did it skip the other whitespaces?
shell sed date
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
11
Most versions ofdatelet you specify the format directly instead so you DON'T have to massage it later with other tools.
– jw013
Sep 14 '12 at 18:14
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I am trying to replace the whitespaces in the output of date with '_' with no success.
$date
Fri Sep 14 14:10:04 EDT 2012
$ date | sed 's/ /_/'
Fri_Sep 14 14:10:24 EDT 2012
As you can see, the last command only replaced the first whitespace by a _'. Why did it skip the other whitespaces?
shell sed date
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
I am trying to replace the whitespaces in the output of date with '_' with no success.
$date
Fri Sep 14 14:10:04 EDT 2012
$ date | sed 's/ /_/'
Fri_Sep 14 14:10:24 EDT 2012
As you can see, the last command only replaced the first whitespace by a _'. Why did it skip the other whitespaces?
shell sed date
shell sed date
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
asked Sep 14 '12 at 18:12
Amelio Vazquez-Reina
12.2k52127228
12.2k52127228
11
Most versions ofdatelet you specify the format directly instead so you DON'T have to massage it later with other tools.
– jw013
Sep 14 '12 at 18:14
add a comment |
11
Most versions ofdatelet you specify the format directly instead so you DON'T have to massage it later with other tools.
– jw013
Sep 14 '12 at 18:14
11
11
Most versions of
date let you specify the format directly instead so you DON'T have to massage it later with other tools.– jw013
Sep 14 '12 at 18:14
Most versions of
date let you specify the format directly instead so you DON'T have to massage it later with other tools.– jw013
Sep 14 '12 at 18:14
add a comment |
2 Answers
2
active
oldest
votes
up vote
8
down vote
accepted
Try:
$ date | tr ' ' '_'
or
$ date | sed 's/ /_/g'
Your command only replaced the first matching instance from the date input because that is the default behaviour of sed. By adding the g (global replacement) option to the end of the command, sed will instead match and replace all occurrences of the expression.
answered Sep 14 '12 at 18:14
tojrobinson
59637
1
In a case like this,tris faster than a regexp substitution.
– JRFerguson
Sep 14 '12 at 19:36
add a comment |
up vote
6
down vote
Just my 2 cents. If you want a date as a single word, a good format is the ISO 8601 standard 2012-09-14T21:08:12. It is terse, unambiguous, and its chronological order is the same as its alphabetical order.
date +%Y-%m-%dT%T
which on some systems you may even write as
date +%FT%T
Beware though that in time zones that implement DSTs, that's still ambiguous. Adding %z removes the ambiguity, but doesn't help with sorting. Another option is to display the UTC time (with -u) or the Unix epoch time (%s is some implementations) which is independent of time zones.
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
8
down vote
accepted
Try:
$ date | tr ' ' '_'
or
$ date | sed 's/ /_/g'
Your command only replaced the first matching instance from the date input because that is the default behaviour of sed. By adding the g (global replacement) option to the end of the command, sed will instead match and replace all occurrences of the expression.
answered Sep 14 '12 at 18:14
tojrobinson
59637
1
In a case like this,tris faster than a regexp substitution.
– JRFerguson
Sep 14 '12 at 19:36
add a comment |
up vote
8
down vote
accepted
Try:
$ date | tr ' ' '_'
or
$ date | sed 's/ /_/g'
Your command only replaced the first matching instance from the date input because that is the default behaviour of sed. By adding the g (global replacement) option to the end of the command, sed will instead match and replace all occurrences of the expression.
answered Sep 14 '12 at 18:14
tojrobinson
59637
1
In a case like this,tris faster than a regexp substitution.
– JRFerguson
Sep 14 '12 at 19:36
add a comment |
up vote
8
down vote
accepted
up vote
8
down vote
accepted
Try:
$ date | tr ' ' '_'
or
$ date | sed 's/ /_/g'
Your command only replaced the first matching instance from the date input because that is the default behaviour of sed. By adding the g (global replacement) option to the end of the command, sed will instead match and replace all occurrences of the expression.
answered Sep 14 '12 at 18:14
tojrobinson
59637
Try:
$ date | tr ' ' '_'
or
$ date | sed 's/ /_/g'
Your command only replaced the first matching instance from the date input because that is the default behaviour of sed. By adding the g (global replacement) option to the end of the command, sed will instead match and replace all occurrences of the expression.
answered Sep 14 '12 at 18:14
tojrobinson
59637
edited Sep 14 '12 at 18:52
answered Sep 14 '12 at 18:14
tojrobinson
59637
answered Sep 14 '12 at 18:14
tojrobinson
59637
answered Sep 14 '12 at 18:14
tojrobinson
59637
59637
1
In a case like this,tris faster than a regexp substitution.
– JRFerguson
Sep 14 '12 at 19:36
add a comment |
1
In a case like this,tris faster than a regexp substitution.
– JRFerguson
Sep 14 '12 at 19:36
1
1
In a case like this,
tr is faster than a regexp substitution.– JRFerguson
Sep 14 '12 at 19:36
In a case like this,
tr is faster than a regexp substitution.– JRFerguson
Sep 14 '12 at 19:36
add a comment |
up vote
6
down vote
Just my 2 cents. If you want a date as a single word, a good format is the ISO 8601 standard 2012-09-14T21:08:12. It is terse, unambiguous, and its chronological order is the same as its alphabetical order.
date +%Y-%m-%dT%T
which on some systems you may even write as
date +%FT%T
Beware though that in time zones that implement DSTs, that's still ambiguous. Adding %z removes the ambiguity, but doesn't help with sorting. Another option is to display the UTC time (with -u) or the Unix epoch time (%s is some implementations) which is independent of time zones.
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
add a comment |
up vote
6
down vote
Just my 2 cents. If you want a date as a single word, a good format is the ISO 8601 standard 2012-09-14T21:08:12. It is terse, unambiguous, and its chronological order is the same as its alphabetical order.
date +%Y-%m-%dT%T
which on some systems you may even write as
date +%FT%T
Beware though that in time zones that implement DSTs, that's still ambiguous. Adding %z removes the ambiguity, but doesn't help with sorting. Another option is to display the UTC time (with -u) or the Unix epoch time (%s is some implementations) which is independent of time zones.
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
add a comment |
up vote
6
down vote
up vote
6
down vote
Just my 2 cents. If you want a date as a single word, a good format is the ISO 8601 standard 2012-09-14T21:08:12. It is terse, unambiguous, and its chronological order is the same as its alphabetical order.
date +%Y-%m-%dT%T
which on some systems you may even write as
date +%FT%T
Beware though that in time zones that implement DSTs, that's still ambiguous. Adding %z removes the ambiguity, but doesn't help with sorting. Another option is to display the UTC time (with -u) or the Unix epoch time (%s is some implementations) which is independent of time zones.
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
Just my 2 cents. If you want a date as a single word, a good format is the ISO 8601 standard 2012-09-14T21:08:12. It is terse, unambiguous, and its chronological order is the same as its alphabetical order.
date +%Y-%m-%dT%T
which on some systems you may even write as
date +%FT%T
Beware though that in time zones that implement DSTs, that's still ambiguous. Adding %z removes the ambiguity, but doesn't help with sorting. Another option is to display the UTC time (with -u) or the Unix epoch time (%s is some implementations) which is independent of time zones.
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
edited Nov 26 at 12:30
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
answered Sep 14 '12 at 20:17
Stéphane Chazelas
296k54559903
296k54559903
add a comment |
add a comment |
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11
Most versions of
datelet you specify the format directly instead so you DON'T have to massage it later with other tools.– jw013
Sep 14 '12 at 18:14