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Cursor disappears when running `top -n1 | head`
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up vote
3
down vote
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When running
top -n1 | head
the terminal's cursor disappears.
Running top -n1 brings it back.
Tested in gnome-terminal and tilix in Ubuntu 16.04 and CentOS 7.5.
Running top -n1 | tail doesn't have this issue, so I think, something at the end of top output let the cursor reappear which is not executed when printing the head only.
What causes this and how can I get back the cursor more elegantly ?
terminal gnome-terminal top cursor
asked 1 hour ago
RoVo
1,416211
add a comment |Â
up vote
3
down vote
favorite
When running
top -n1 | head
the terminal's cursor disappears.
Running top -n1 brings it back.
Tested in gnome-terminal and tilix in Ubuntu 16.04 and CentOS 7.5.
Running top -n1 | tail doesn't have this issue, so I think, something at the end of top output let the cursor reappear which is not executed when printing the head only.
What causes this and how can I get back the cursor more elegantly ?
terminal gnome-terminal top cursor
asked 1 hour ago
RoVo
1,416211
I can also get it back with runningtput cnorm. (via)
– RoVo
51 mins ago
add a comment |Â
up vote
3
down vote
favorite
up vote
3
down vote
favorite
When running
top -n1 | head
the terminal's cursor disappears.
Running top -n1 brings it back.
Tested in gnome-terminal and tilix in Ubuntu 16.04 and CentOS 7.5.
Running top -n1 | tail doesn't have this issue, so I think, something at the end of top output let the cursor reappear which is not executed when printing the head only.
What causes this and how can I get back the cursor more elegantly ?
terminal gnome-terminal top cursor
asked 1 hour ago
RoVo
1,416211
When running
top -n1 | head
the terminal's cursor disappears.
Running top -n1 brings it back.
Tested in gnome-terminal and tilix in Ubuntu 16.04 and CentOS 7.5.
Running top -n1 | tail doesn't have this issue, so I think, something at the end of top output let the cursor reappear which is not executed when printing the head only.
What causes this and how can I get back the cursor more elegantly ?
terminal gnome-terminal top cursor
terminal gnome-terminal top cursor
asked 1 hour ago
RoVo
1,416211
asked 1 hour ago
RoVo
1,416211
edited 1 hour ago
asked 1 hour ago
RoVo
1,416211
asked 1 hour ago
RoVo
1,416211
asked 1 hour ago
RoVo
1,416211
1,416211
I can also get it back with runningtput cnorm. (via)
– RoVo
51 mins ago
add a comment |Â
I can also get it back with runningtput cnorm. (via)
– RoVo
51 mins ago
I can also get it back with running
tput cnorm. (via)– RoVo
51 mins ago
I can also get it back with running
tput cnorm. (via)– RoVo
51 mins ago
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
5
down vote
Best way IMHO is to make top use "batch" mode which is intended to be used with non-interactive use cases such as piping to another program or to a file.
So, this
top -n1 -b | head
won't be leaving the shell without a cursor.
As for the why the cursor disappears...
Since top is an interactive program, it "messes" with the terminal in order to grab input, scroll content, etc, and it hides the cursor.
When terminating it has to restore the cursor display, and it does so by sending a control code to the terminal itself.
By piping the command through head, this control code won't get through (head prints just the firs 10 lines by default, and the output of top + control codes to restore the terminal state is >10 lines).
As a matter of fact, if you give head enough lines to print, the cursor appears!
For example,
top -n1 | head -n100
leaves a cursor on my system.
answered 1 hour ago
Mr Shunz
2,23711617
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
5
down vote
Best way IMHO is to make top use "batch" mode which is intended to be used with non-interactive use cases such as piping to another program or to a file.
So, this
top -n1 -b | head
won't be leaving the shell without a cursor.
As for the why the cursor disappears...
Since top is an interactive program, it "messes" with the terminal in order to grab input, scroll content, etc, and it hides the cursor.
When terminating it has to restore the cursor display, and it does so by sending a control code to the terminal itself.
By piping the command through head, this control code won't get through (head prints just the firs 10 lines by default, and the output of top + control codes to restore the terminal state is >10 lines).
As a matter of fact, if you give head enough lines to print, the cursor appears!
For example,
top -n1 | head -n100
leaves a cursor on my system.
answered 1 hour ago
Mr Shunz
2,23711617
add a comment |Â
up vote
5
down vote
Best way IMHO is to make top use "batch" mode which is intended to be used with non-interactive use cases such as piping to another program or to a file.
So, this
top -n1 -b | head
won't be leaving the shell without a cursor.
As for the why the cursor disappears...
Since top is an interactive program, it "messes" with the terminal in order to grab input, scroll content, etc, and it hides the cursor.
When terminating it has to restore the cursor display, and it does so by sending a control code to the terminal itself.
By piping the command through head, this control code won't get through (head prints just the firs 10 lines by default, and the output of top + control codes to restore the terminal state is >10 lines).
As a matter of fact, if you give head enough lines to print, the cursor appears!
For example,
top -n1 | head -n100
leaves a cursor on my system.
answered 1 hour ago
Mr Shunz
2,23711617
add a comment |Â
up vote
5
down vote
up vote
5
down vote
Best way IMHO is to make top use "batch" mode which is intended to be used with non-interactive use cases such as piping to another program or to a file.
So, this
top -n1 -b | head
won't be leaving the shell without a cursor.
As for the why the cursor disappears...
Since top is an interactive program, it "messes" with the terminal in order to grab input, scroll content, etc, and it hides the cursor.
When terminating it has to restore the cursor display, and it does so by sending a control code to the terminal itself.
By piping the command through head, this control code won't get through (head prints just the firs 10 lines by default, and the output of top + control codes to restore the terminal state is >10 lines).
As a matter of fact, if you give head enough lines to print, the cursor appears!
For example,
top -n1 | head -n100
leaves a cursor on my system.
answered 1 hour ago
Mr Shunz
2,23711617
Best way IMHO is to make top use "batch" mode which is intended to be used with non-interactive use cases such as piping to another program or to a file.
So, this
top -n1 -b | head
won't be leaving the shell without a cursor.
As for the why the cursor disappears...
Since top is an interactive program, it "messes" with the terminal in order to grab input, scroll content, etc, and it hides the cursor.
When terminating it has to restore the cursor display, and it does so by sending a control code to the terminal itself.
By piping the command through head, this control code won't get through (head prints just the firs 10 lines by default, and the output of top + control codes to restore the terminal state is >10 lines).
As a matter of fact, if you give head enough lines to print, the cursor appears!
For example,
top -n1 | head -n100
leaves a cursor on my system.
answered 1 hour ago
Mr Shunz
2,23711617
edited 1 hour ago
answered 1 hour ago
Mr Shunz
2,23711617
answered 1 hour ago
Mr Shunz
2,23711617
answered 1 hour ago
Mr Shunz
2,23711617
2,23711617
add a comment |Â
add a comment |Â
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I can also get it back with running
tput cnorm. (via)– RoVo
51 mins ago