How can I know if a command works with pipe?
up vote
2
down vote
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I saw this command:
docker inspect --format '{{.State.Running}}' $(docker ps -lq)
and this:
docker ps -l -q|while read cid b; do docker inspect -f '{{ .State.Running }}' $cid; done;
My question is why it cannot be written as:
docker ps -l -q|docker inspect -f '{{.State.Running}}'
If that was because docker inspect does not work with pipe, how can I know which command can and which cannot?
pipe docker
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
add a comment |
up vote
2
down vote
favorite
I saw this command:
docker inspect --format '{{.State.Running}}' $(docker ps -lq)
and this:
docker ps -l -q|while read cid b; do docker inspect -f '{{ .State.Running }}' $cid; done;
My question is why it cannot be written as:
docker ps -l -q|docker inspect -f '{{.State.Running}}'
If that was because docker inspect does not work with pipe, how can I know which command can and which cannot?
pipe docker
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I saw this command:
docker inspect --format '{{.State.Running}}' $(docker ps -lq)
and this:
docker ps -l -q|while read cid b; do docker inspect -f '{{ .State.Running }}' $cid; done;
My question is why it cannot be written as:
docker ps -l -q|docker inspect -f '{{.State.Running}}'
If that was because docker inspect does not work with pipe, how can I know which command can and which cannot?
pipe docker
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
I saw this command:
docker inspect --format '{{.State.Running}}' $(docker ps -lq)
and this:
docker ps -l -q|while read cid b; do docker inspect -f '{{ .State.Running }}' $cid; done;
My question is why it cannot be written as:
docker ps -l -q|docker inspect -f '{{.State.Running}}'
If that was because docker inspect does not work with pipe, how can I know which command can and which cannot?
pipe docker
pipe docker
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
edited Nov 25 at 15:00
Rui F Ribeiro
38.3k1475126
38.3k1475126
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
asked Oct 2 '15 at 10:59
Xiao Peng - ZenUML.com
1214
1214
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
up vote
2
down vote
Pipe takes the output of the first program and passes it into the next program. In a sense, it pretends to be a user typing input into the second program in a terminal. So, if you can run the program and type in (for example) a list of files to operate on while the program is running, then you can do the same thing with a pipe.
You may see hints to what can be done using pipes in a program's manual. For instance, man wget mentions the -i argument, and that -i - will read files from standard input, also called STDIN. So you could cat list-of-links.txt | wget -i -, or more effectively wget -i - < list-of-links.txt.
answered Oct 2 '15 at 11:25
tripflag
43524
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
Pipe takes the output of the first program and passes it into the next program. In a sense, it pretends to be a user typing input into the second program in a terminal. So, if you can run the program and type in (for example) a list of files to operate on while the program is running, then you can do the same thing with a pipe.
You may see hints to what can be done using pipes in a program's manual. For instance, man wget mentions the -i argument, and that -i - will read files from standard input, also called STDIN. So you could cat list-of-links.txt | wget -i -, or more effectively wget -i - < list-of-links.txt.
answered Oct 2 '15 at 11:25
tripflag
43524
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
add a comment |
up vote
2
down vote
Pipe takes the output of the first program and passes it into the next program. In a sense, it pretends to be a user typing input into the second program in a terminal. So, if you can run the program and type in (for example) a list of files to operate on while the program is running, then you can do the same thing with a pipe.
You may see hints to what can be done using pipes in a program's manual. For instance, man wget mentions the -i argument, and that -i - will read files from standard input, also called STDIN. So you could cat list-of-links.txt | wget -i -, or more effectively wget -i - < list-of-links.txt.
answered Oct 2 '15 at 11:25
tripflag
43524
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
add a comment |
up vote
2
down vote
up vote
2
down vote
Pipe takes the output of the first program and passes it into the next program. In a sense, it pretends to be a user typing input into the second program in a terminal. So, if you can run the program and type in (for example) a list of files to operate on while the program is running, then you can do the same thing with a pipe.
You may see hints to what can be done using pipes in a program's manual. For instance, man wget mentions the -i argument, and that -i - will read files from standard input, also called STDIN. So you could cat list-of-links.txt | wget -i -, or more effectively wget -i - < list-of-links.txt.
answered Oct 2 '15 at 11:25
tripflag
43524
Pipe takes the output of the first program and passes it into the next program. In a sense, it pretends to be a user typing input into the second program in a terminal. So, if you can run the program and type in (for example) a list of files to operate on while the program is running, then you can do the same thing with a pipe.
You may see hints to what can be done using pipes in a program's manual. For instance, man wget mentions the -i argument, and that -i - will read files from standard input, also called STDIN. So you could cat list-of-links.txt | wget -i -, or more effectively wget -i - < list-of-links.txt.
answered Oct 2 '15 at 11:25
tripflag
43524
answered Oct 2 '15 at 11:25
tripflag
43524
answered Oct 2 '15 at 11:25
tripflag
43524
answered Oct 2 '15 at 11:25
tripflag
43524
43524
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
add a comment |
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
A caveat to this is that some programs acts differently when the input comes from or goes to a pipe, compared from when connected to a terminal.
– Kusalananda
Nov 25 at 15:03
add a comment |
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