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Old 12-12-2010, 09:25 AM   #1
courteous
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Question Print all PID folders from /proc line-by-line with this format (( PID: command-line ))


How do you extract all numeric folders from PIDs variable, which is defined as:
Code:
PIDs="$(ls -v /proc/)"  # -v for numeric sort
I would like to print all PID (ie. numeric) folders from /proc folder. This does not work:
Code:
numberOfPIDs="$(ls /proc/ | wc -l)"

for ((x=0; x < $numberOfPIDs; x++)); do
	echo "$PIDsource | cut -d' ' -f$x"
done

Last edited by courteous; 12-12-2010 at 03:30 PM. Reason: made more precise title
 
Old 12-12-2010, 09:36 AM   #2
colucix
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Code:
ls -dv [1-9]*
lists all the PID directories under /proc numerically sorted.
 
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Old 12-12-2010, 02:26 PM   #3
courteous
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Excellent.
How can I use your snippet outside /proc folder? Why this doesn't work:
Code:
ls -dv [1-9]* /proc/

Last edited by courteous; 12-12-2010 at 02:57 PM.
 
Old 12-12-2010, 03:01 PM   #4
impert
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Code:
ls -dv /proc/[1-9]*
 
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Old 12-12-2010, 03:09 PM   #5
courteous
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This for loop is much better, but it still gives plenty of errors:
Code:
PIDlist="$(ls -dv /proc/[1-9]* | cut -d '/' -f3)" # I need only PIDs
PIDnumber="$(ls /proc/ | wc -l)"

for i in "$PIDlist"; do
	printf "%4u | %10s\n" "$i" "$(cat /proc/$i/cmdline)"
done
Error example: cat: 4: No such file or directory. Indeed, in terminal cat /proc/4/cmdline returns nothing.

Last edited by courteous; 12-12-2010 at 03:12 PM.
 
Old 12-12-2010, 04:27 PM   #6
colucix
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Keep it simple. You might loop over the /proc/PID directories and use parameter substitution or the basename command to retrieve PID. Example:
Code:
for i in /proc/[1-9]*
do
  command="$(cat $i/cmdline)"
  command=${command:-<not available>}         # if command is not set or empty use default
  printf "%5d | %s\n" ${i##*/} "$command"     # ${i##*/} is the same as $(basename $i)
done | sort -k1n
Hope this helps.
 
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Old 12-12-2010, 04:36 PM   #7
courteous
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What do hash-hash-star-slash, that is ${i##*/}, in printf do?

EDIT: Oh, I'm sorry, now I see it in comment. Forward to man basename!

Thank you again.

Last edited by courteous; 12-12-2010 at 04:38 PM.
 
Old 12-12-2010, 04:47 PM   #8
colucix
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Actually it is substring removal. Look at the advanced bash scripting guide, here.
Code:
${string##substring}

    Deletes longest match of $substring from front of $string.
In this case it deletes the longest match of any string * followed by a slash, acting as the basename command.
 
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