What does bashrc PS1 check [ “$PS1” = “\s-\v\$ ” ] mean?
In /etc/bashrc file in Fedora/Red Hat I see following line:
[ "$PS1" = "\s-\v\$ " ] && PS1="[u@h W]\$ "
What is the check being done in [ "$PS1" = "\s-\v\$ " ] and why is PS1 set only if the test succeeds?
bash bashrc
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
add a comment |
In /etc/bashrc file in Fedora/Red Hat I see following line:
[ "$PS1" = "\s-\v\$ " ] && PS1="[u@h W]\$ "
What is the check being done in [ "$PS1" = "\s-\v\$ " ] and why is PS1 set only if the test succeeds?
bash bashrc
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
add a comment |
In /etc/bashrc file in Fedora/Red Hat I see following line:
[ "$PS1" = "\s-\v\$ " ] && PS1="[u@h W]\$ "
What is the check being done in [ "$PS1" = "\s-\v\$ " ] and why is PS1 set only if the test succeeds?
bash bashrc
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
In /etc/bashrc file in Fedora/Red Hat I see following line:
[ "$PS1" = "\s-\v\$ " ] && PS1="[u@h W]\$ "
What is the check being done in [ "$PS1" = "\s-\v\$ " ] and why is PS1 set only if the test succeeds?
bash bashrc
bash bashrc
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
asked Aug 10 '17 at 10:01
AkilanAkilan
1465
1465
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
(I debated whether to make this an answer since it's such a swag but here ya go...)
Just a theory but the first form (e.g. bash-3.2.1$) looks like the prompt I often see when logged in as root or other "non-user" account . The second, overriding form (e.g. [joeblow@myhost /tmp]$) is more user-centric. So maybe this is to detect when going from a system account to user account...then, and only then, change to a more appropriate prompt. Otherwise assume someone would want to preserve the current prompt.
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
add a comment |
The check being done is a string comparison =. It's comparing the value of $PS1 to the string s-v$, where the backslashes need to be escaped in the string so that they get compared to actual backslashes instead of attempting to escape the following character.
The && syntax is the part that sets PS1 only if the preceding test succeeds.
The overall logic here is apparently to update PS1 only if it was previously set to a specific value.
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
add a comment |
I believe the comparison is checking to see if the shell is an interactive session. s-v$ as a $PS1 var evaluates to bash-5.0$ on my machine. See the differences here:
Jonathans-Air:~ lirum$ bash
bash-5.0$ echo "$PS1"
s-v$
bash-5.0$ exit
exit
Jonathans-Air:~ lirum$ echo "$PS1"
h:W u$
answered 1 hour ago
LirumLirum
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
(I debated whether to make this an answer since it's such a swag but here ya go...)
Just a theory but the first form (e.g. bash-3.2.1$) looks like the prompt I often see when logged in as root or other "non-user" account . The second, overriding form (e.g. [joeblow@myhost /tmp]$) is more user-centric. So maybe this is to detect when going from a system account to user account...then, and only then, change to a more appropriate prompt. Otherwise assume someone would want to preserve the current prompt.
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
add a comment |
(I debated whether to make this an answer since it's such a swag but here ya go...)
Just a theory but the first form (e.g. bash-3.2.1$) looks like the prompt I often see when logged in as root or other "non-user" account . The second, overriding form (e.g. [joeblow@myhost /tmp]$) is more user-centric. So maybe this is to detect when going from a system account to user account...then, and only then, change to a more appropriate prompt. Otherwise assume someone would want to preserve the current prompt.
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
add a comment |
(I debated whether to make this an answer since it's such a swag but here ya go...)
Just a theory but the first form (e.g. bash-3.2.1$) looks like the prompt I often see when logged in as root or other "non-user" account . The second, overriding form (e.g. [joeblow@myhost /tmp]$) is more user-centric. So maybe this is to detect when going from a system account to user account...then, and only then, change to a more appropriate prompt. Otherwise assume someone would want to preserve the current prompt.
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
(I debated whether to make this an answer since it's such a swag but here ya go...)
Just a theory but the first form (e.g. bash-3.2.1$) looks like the prompt I often see when logged in as root or other "non-user" account . The second, overriding form (e.g. [joeblow@myhost /tmp]$) is more user-centric. So maybe this is to detect when going from a system account to user account...then, and only then, change to a more appropriate prompt. Otherwise assume someone would want to preserve the current prompt.
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
edited Aug 10 '17 at 14:17
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
answered Aug 10 '17 at 14:12
B LayerB Layer
4,0641625
4,0641625
add a comment |
add a comment |
The check being done is a string comparison =. It's comparing the value of $PS1 to the string s-v$, where the backslashes need to be escaped in the string so that they get compared to actual backslashes instead of attempting to escape the following character.
The && syntax is the part that sets PS1 only if the preceding test succeeds.
The overall logic here is apparently to update PS1 only if it was previously set to a specific value.
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
add a comment |
The check being done is a string comparison =. It's comparing the value of $PS1 to the string s-v$, where the backslashes need to be escaped in the string so that they get compared to actual backslashes instead of attempting to escape the following character.
The && syntax is the part that sets PS1 only if the preceding test succeeds.
The overall logic here is apparently to update PS1 only if it was previously set to a specific value.
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
add a comment |
The check being done is a string comparison =. It's comparing the value of $PS1 to the string s-v$, where the backslashes need to be escaped in the string so that they get compared to actual backslashes instead of attempting to escape the following character.
The && syntax is the part that sets PS1 only if the preceding test succeeds.
The overall logic here is apparently to update PS1 only if it was previously set to a specific value.
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
The check being done is a string comparison =. It's comparing the value of $PS1 to the string s-v$, where the backslashes need to be escaped in the string so that they get compared to actual backslashes instead of attempting to escape the following character.
The && syntax is the part that sets PS1 only if the preceding test succeeds.
The overall logic here is apparently to update PS1 only if it was previously set to a specific value.
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
answered Aug 10 '17 at 11:16
Jeff SchallerJeff Schaller
43.4k1160140
43.4k1160140
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
add a comment |
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
I understand that it is string comparison and && being used as a test. My question rather was about significance of that string and "why is PS1 set only if the test succeeds".
– Akilan
Aug 10 '17 at 11:45
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
The poster already acknowledged that && was testing for the success of the previous command and so the answer doesn't give the required response,
– Raman Sailopal
Aug 10 '17 at 12:52
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
I think you'd have to ask the maintainers of that file to ask why it is set that way.
– Jeff Schaller
Aug 10 '17 at 22:49
add a comment |
I believe the comparison is checking to see if the shell is an interactive session. s-v$ as a $PS1 var evaluates to bash-5.0$ on my machine. See the differences here:
Jonathans-Air:~ lirum$ bash
bash-5.0$ echo "$PS1"
s-v$
bash-5.0$ exit
exit
Jonathans-Air:~ lirum$ echo "$PS1"
h:W u$
answered 1 hour ago
LirumLirum
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
I believe the comparison is checking to see if the shell is an interactive session. s-v$ as a $PS1 var evaluates to bash-5.0$ on my machine. See the differences here:
Jonathans-Air:~ lirum$ bash
bash-5.0$ echo "$PS1"
s-v$
bash-5.0$ exit
exit
Jonathans-Air:~ lirum$ echo "$PS1"
h:W u$
answered 1 hour ago
LirumLirum
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
I believe the comparison is checking to see if the shell is an interactive session. s-v$ as a $PS1 var evaluates to bash-5.0$ on my machine. See the differences here:
Jonathans-Air:~ lirum$ bash
bash-5.0$ echo "$PS1"
s-v$
bash-5.0$ exit
exit
Jonathans-Air:~ lirum$ echo "$PS1"
h:W u$
answered 1 hour ago
LirumLirum
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I believe the comparison is checking to see if the shell is an interactive session. s-v$ as a $PS1 var evaluates to bash-5.0$ on my machine. See the differences here:
Jonathans-Air:~ lirum$ bash
bash-5.0$ echo "$PS1"
s-v$
bash-5.0$ exit
exit
Jonathans-Air:~ lirum$ echo "$PS1"
h:W u$
answered 1 hour ago
LirumLirum
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 1 hour ago
LirumLirum
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 1 hour ago
LirumLirum
11
answered 1 hour ago
LirumLirum
11
11
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Lirum is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
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