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 $num
shell-script
edited Jan 5 at 16:22
terdon♦
129k32253428
asked Jan 5 at 16:18
User101User101
604
add a comment |
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
edited Jan 5 at 16:22
terdon♦
129k32253428
asked Jan 5 at 16:18
User101User101
604
add a comment |
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
edited Jan 5 at 16:22
terdon♦
129k32253428
asked Jan 5 at 16:18
User101User101
604
Is this possible, if not, is there a better I can do it?
Example:
Number of log entries: 3
log=$(home/admin17/folder/data_log)
read -p "Number of log entries" num
cat $log | tail -n $num
shell-script
shell-script
edited Jan 5 at 16:22
terdon♦
129k32253428
asked Jan 5 at 16:18
User101User101
604
edited Jan 5 at 16:22
terdon♦
129k32253428
asked Jan 5 at 16:18
User101User101
604
edited Jan 5 at 16:22
terdon♦
129k32253428
edited Jan 5 at 16:22
terdon♦
129k32253428
edited Jan 5 at 16:22
terdon♦
129k32253428
129k32253428
asked Jan 5 at 16:18
User101User101
604
asked Jan 5 at 16:18
User101User101
604
asked Jan 5 at 16:18
User101User101
604
604
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
The var=$(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" "$log"
edited Jan 5 at 16:27
Nasir Riley
2,441249
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
Jan 5 at 21:41
add a comment |
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1 Answer
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1 Answer
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The var=$(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" "$log"
edited Jan 5 at 16:27
Nasir Riley
2,441249
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
Jan 5 at 21:41
add a comment |
The var=$(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" "$log"
edited Jan 5 at 16:27
Nasir Riley
2,441249
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
1
Note also that the path is relative to user's current working directory. If the user wants to use same file regardless of where they are currently in the directory tree, the path has to be absolute, so probably/home/admin17/folder/data_log
– Sergiy Kolodyazhnyy
Jan 5 at 21:41
add a comment |
The var=$(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" "$log"
edited Jan 5 at 16:27
Nasir Riley
2,441249
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
The var=$(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 Jan 5 at 16:27
Nasir Riley
2,441249
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
edited Jan 5 at 16:27
Nasir Riley
2,441249
edited Jan 5 at 16:27
Nasir Riley
2,441249
edited Jan 5 at 16:27
Nasir Riley
2,441249
2,441249
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
answered Jan 5 at 16:25
terdon♦terdon
129k32253428
129k32253428
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
Jan 5 at 21:41
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
Jan 5 at 21:41
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
Jan 5 at 21:41
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
Jan 5 at 21:41
add a comment |
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