Can I attach a variable to a tail command?
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
add a comment |
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
add a comment |
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
shell-script
edited yesterday
terdon♦
128k31252427
128k31252427
asked yesterday
User101
584
584
add a comment |
add a comment |
1 Answer
1
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oldest
votes
The var=$(command)
notation runs command
and assigns its output to var
. Since home/admin17/folder/data_log
is a file and not a command, that should give you an error:
log=$(home/admin17/folder/data_log)
bash: home/admin17/folder/data_log: command not found
If you want to save the file name as a variable, you need:
log=home/admin17/folder/data_log
Then, the rest should work as you expect:
log=home/admin17/folder/data_log
read -p "Number of log entries" num
cat $log | tail -n $num
Or, avoiding the Useless Use of Cat (UUoC):
log=home/admin17/folder/data_log
read -p "Number of log entries: " num
tail -n "$num" "$log"
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The var=$(command)
notation runs command
and assigns its output to var
. Since home/admin17/folder/data_log
is a file and not a command, that should give you an error:
log=$(home/admin17/folder/data_log)
bash: home/admin17/folder/data_log: command not found
If you want to save the file name as a variable, you need:
log=home/admin17/folder/data_log
Then, the rest should work as you expect:
log=home/admin17/folder/data_log
read -p "Number of log entries" num
cat $log | tail -n $num
Or, avoiding the Useless Use of Cat (UUoC):
log=home/admin17/folder/data_log
read -p "Number of log entries: " num
tail -n "$num" "$log"
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
add a comment |
The var=$(command)
notation runs command
and assigns its output to var
. Since home/admin17/folder/data_log
is a file and not a command, that should give you an error:
log=$(home/admin17/folder/data_log)
bash: home/admin17/folder/data_log: command not found
If you want to save the file name as a variable, you need:
log=home/admin17/folder/data_log
Then, the rest should work as you expect:
log=home/admin17/folder/data_log
read -p "Number of log entries" num
cat $log | tail -n $num
Or, avoiding the Useless Use of Cat (UUoC):
log=home/admin17/folder/data_log
read -p "Number of log entries: " num
tail -n "$num" "$log"
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
add a comment |
The var=$(command)
notation runs command
and assigns its output to var
. Since home/admin17/folder/data_log
is a file and not a command, that should give you an error:
log=$(home/admin17/folder/data_log)
bash: home/admin17/folder/data_log: command not found
If you want to save the file name as a variable, you need:
log=home/admin17/folder/data_log
Then, the rest should work as you expect:
log=home/admin17/folder/data_log
read -p "Number of log entries" num
cat $log | tail -n $num
Or, avoiding the Useless Use of Cat (UUoC):
log=home/admin17/folder/data_log
read -p "Number of log entries: " num
tail -n "$num" "$log"
The var=$(command)
notation runs command
and assigns its output to var
. Since home/admin17/folder/data_log
is a file and not a command, that should give you an error:
log=$(home/admin17/folder/data_log)
bash: home/admin17/folder/data_log: command not found
If you want to save the file name as a variable, you need:
log=home/admin17/folder/data_log
Then, the rest should work as you expect:
log=home/admin17/folder/data_log
read -p "Number of log entries" num
cat $log | tail -n $num
Or, avoiding the Useless Use of Cat (UUoC):
log=home/admin17/folder/data_log
read -p "Number of log entries: " num
tail -n "$num" "$log"
edited yesterday
Nasir Riley
2,366239
2,366239
answered yesterday
terdon♦
128k31252427
128k31252427
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
add a comment |
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
1
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably
/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably
/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
yesterday
add a comment |
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