Commands using strace sorted by votes

Commands using strace (25)

sorted by

intercept stdout/stderr of another process
This is sample output - yours may be different.
59

strace -ff -e trace=write -e write=1,2 -p SOME_PID

oernii2 · 2010-04-20 08:55:54 2
List files accessed by a command

Can be run as a script `ftrace` if my_command is substrituted with "$@" It is useful when running a command that fails and you have the feeling it is accessing a file you are not aware of. Show Sample Output
This is sample output - yours may be different.
```
$ strace -ff -e trace=file chmod 755 ~/bin/ftrace 2>&1 | perl -ne 's/^[^"]+"(([^\\"]|\\[\\"nt])*)".*/$1/ && print'
/bin/chmod
/etc/ld.so.nohwcap
/etc/ld.so.preload
/etc/ld.so.cache
/etc/ld.so.nohwcap
/lib/x86_64-linux-gnu/libc.so.6
/usr/lib/locale/locale-archive
/home/tange/bin/ftrace
/home/tange/bin/ftrace
```
17

strace -ff -e trace=file my_command 2>&1 | perl -ne 's/^[^"]+"(([^\\"]|\\[\\"nt])*)".*/$1/ && print'

unixmonkey8046 · 2011-08-16 15:00:18 2
intercept stdout/stderr of another process

similar to the previous command, but with more friendly output (tested on linux)
This is sample output - yours may be different.
10

strace -ff -e write=1,2 -s 1024 -p PID 2>&1 | grep "^ |" | cut -c11-60 | sed -e 's/ //g' | xxd -r -p

systemj · 2010-04-23 16:22:17 0
Determine what an process is actually doing
This is sample output - yours may be different.
7

sudo strace -pXXXX -e trace=file

tolginho · 2009-12-01 15:27:48 2
See why a program can't seem to access a file

Sometimes a program refuses to read a file and you're not sure why. You may have display_errors turned off for PHP or something. In this example, fopen('/var/www/test/foo.txt') was called but doesn't have read access to foo.txt. Strace can tell you what went wrong. E.g., if php doesn't have read access to the file, strace will say "EACCESS (Permission denied)". Or, if the file path you gave doesn't exist, strace will say "ENOENT (No such file or directory)", etc. This works for any program you can run from the command-line, e.g., strace python myapp.py -e open,access... Note: the above command uses php-cli, not mod_php, which is a different SAPI with diff configs, etc. Show Sample Output
This is sample output - yours may be different.
```
open("/var/www/test/filename.txt", O_RDONLY|O_LARGEFILE) = -1 EACCES (Permission denied)
```
7

strace php tias.php -e open,access 2>&1 | grep foo.txt

rkulla · 2010-04-20 19:42:42 0

List all accessed configuration files while executing a program in linux terminal (improved version)

Last listed files presumably have higher precedency then files listed first, i.e. configuration files in the personal .config directory will be listed last and their config parameters will be more authoritative then default config parameters defined in /etc directory which are usually listed above them. If you replace ".conf" with ".ini" in the command, initial files will be listed instead of config files. If you do not like to list multiple access to the same config file, pipe to "uniq" or "uniq -c" to prefix lines by the number of occurrences Show Sample Output

strace 2>&1 <any_executable> |egrep -o "\".*\.conf\""

knoppix5 · 2020-07-31 10:57:29 1

trace the system calls made by a process (and its children)

strace can be invaluable in trying to figure out what the heck some misbehaving program is doing. There are number of useful flags to limit and control its output, and to attach to already running programs. (See also 'ltrace'.) Show Sample Output

strace -f -s 512 -v ls -l

mkc · 2009-02-06 02:45:33 0

Catch a proccess from a user and strace it.

It sits there in a loop waiting for a proccess from that user to spawn. When it does it will attach strace to it Show Sample Output
This is sample output - yours may be different.
```
It sits there in a loop waiting for a proccess from that user to spawn.
```
4

x=1; while [ $x = 1 ]; do process=`pgrep -u username`; if [ $process ]; then x=0; fi; done; strace -vvtf -s 256 -p $process

dimentox · 2009-09-22 16:46:27 1
Find files that were modified by a given command

Traces the system calls of a program. See http://linuxhelp.blogspot.com/2006/05/strace-very-powerful-troubleshooting.html for more information.
This is sample output - yours may be different.
3

strace <name of the program>

eitland · 2009-08-31 20:42:50 6
Strace all signals processes based on a name ( The processes already started... ) with bash built-in

Especially for sysadmins when they don't want to waste time to add -p flag on the N processes of a processname. In the old school, you did ; pgrep processname and typing strace -f -p 456 -p 678 -p 974... You can add -f argument to the function. That way, the function will deal with pgrep to match the command-line. Example : processname -f jrockit
This is sample output - yours may be different.
3

straceprocessname(){ x=( $(pgrep "$@") ); [[ ${x[@]} ]] || return 1; strace -vf ${x[@]/#/-p }; }

sputnick · 2009-12-03 00:04:39 1

Terminal Escape Code Zen - Strace and Tput

Depending on the TERM, the terminfo version, ncurses version, etc.. you may be using a varied assortment of terminal escape codes. With this command you can easily find out exactly what is going on.. This is terminal escape zen! ( 2>&2 strace -f -F -e write -s 1000 sh -c 'echo -e "initc\nis2\ncnorm\nrmso\nsgr0" | tput -S' 2>&1 ) | grep -o '"\\[^"]*"' --color=always "\33]4;%p1%d;rgb:%p2%{255}%*%{1000}%/%2.2X/%p3%{255}%*%{1000}%/%2.2X/%p4%{255}%*%{1000}%/%2.2X\33\\\33[!p\33[?3;4l\33[4l\33>\33[?12l\33[?25h\33[27m\33(B\33[m" Lets say you want to find out what you need to echo in order to get the text to blink.. echo -e "`tput blink`This will blink`tput sgr0` This wont" Now you can use this function instead of calling tput (tput is much smarter for portable code because it works differently depending on the current TERM, and tput -T anyterm works too.) to turn that echo into a much faster executing code. tput queries files, opens files, etc.. but echo is very strait and narrow. So now you can do this: echo -e "\33[5mThis will blink\33(B\33[m This wont" More at http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html Show Sample Output

This is sample output - yours may be different.

$ for cap in `infocmp -1q|sed 's/ *//g'|grep -v '#\||' |cut -d= -f1|tr "\n" ' '`; do echo "$cap: `termtrace $cap 5`"; done
bel: "\7"
blink: "\33[5m"
bold: "\33[1m"
cbt: "\33[Z"
civis: "\33[?25l"
clear: "\33[H\33[2J"
cnorm: "\33[?12l\33[?25h"
cr: "\r"
csr: "\33[6;1r"
cub: "\33[5D"
cub1: "\10"
cud: "\33[5B"
cud1: "\n"
cuf: "\33[5C"
cuf1: "\33[C"
cup: "\33[6;1H"
cuu: "\33[5A"
cuu1: "\33[A"
cvvis: "\33[?12;25h"
dch: "\33[5P"
dch1: "\33[P"
dl: "\33[5M"
dl1: "\33[M"
ech: "\33[5X"
ed: "\33[J"
el: "\33[K"
el1: "\33[1K"
flash: "\33[?5h"
"\33[?5l"
home: "\33[H"
hpa: "\33[6G"
ht: "\t"
hts: "\33H"
ich: "\33[5@"
il: "\33[5L"
il1: "\33[L"
ind: "\n"
indn: "\33[5S"
initc: "\33]4;5;rgb:00/00/00\33\\"
invis: "\33[8m"
is2: "\33[!p\33[?3;4l\33[4l\33>"
kDC: "\33[3;2~"
kEND: "\33[1;2F"
kHOM: "\33[1;2H"
kIC: "\33[2;2~"
kLFT: "\33[1;2D"
kNXT: "\33[6;2~"
kPRV: "\33[5;2~"
kRIT: "\33[1;2C"
kb2: "\33OE"
kbs: "\177"
kcbt: "\33[Z"
kcub1: "\33OD"
kcud1: "\33OB"
kcuf1: "\33OC"
kcuu1: "\33OA"
kdch1: "\33[3~"
kend: "\33OF"
kent: "\33OM"
kf1: "\33OP"
kf10: "\33[21~"
kf11: "\33[23~"
kf12: "\33[24~"
kf13: "\33O2P"
kf14: "\33O2Q"
kf15: "\33O2R"
kf16: "\33O2S"
kf17: "\33[15;2~"
kf18: "\33[17;2~"
kf19: "\33[18;2~"
kf2: "\33OQ"
kf20: "\33[19;2~"
kf21: "\33[20;2~"
kf22: "\33[21;2~"
kf23: "\33[23;2~"
kf24: "\33[24;2~"
kf25: "\33O5P"
kf26: "\33O5Q"
kf27: "\33O5R"
kf28: "\33O5S"
kf29: "\33[15;5~"
kf3: "\33OR"
kf30: "\33[17;5~"
kf31: "\33[18;5~"
kf32: "\33[19;5~"
kf33: "\33[20;5~"
kf34: "\33[21;5~"
kf35: "\33[23;5~"
kf36: "\33[24;5~"
kf37: "\33O6P"
kf38: "\33O6Q"
kf39: "\33O6R"
kf4: "\33OS"
kf40: "\33O6S"
kf41: "\33[15;6~"
kf42: "\33[17;6~"
kf43: "\33[18;6~"
kf44: "\33[19;6~"
kf45: "\33[20;6~"
kf46: "\33[21;6~"
kf47: "\33[23;6~"
kf48: "\33[24;6~"
kf49: "\33O3P"
kf5: "\33[15~"
kf50: "\33O3Q"
kf51: "\33O3R"
kf52: "\33O3S"
kf53: "\33[15;3~"
kf54: "\33[17;3~"
kf55: "\33[18;3~"
kf56: "\33[19;3~"
kf57: "\33[20;3~"
kf58: "\33[21;3~"
kf59: "\33[23;3~"
kf6: "\33[17~"
kf60: "\33[24;3~"
kf61: "\33O4P"
kf62: "\33O4Q"
kf63: "\33O4R"
kf7: "\33[18~"
kf8: "\33[19~"
kf9: "\33[20~"
khome: "\33OH"
kich1: "\33[2~"
kind: "\33[1;2B"
kmous: "\33[M"
knp: "\33[6~"
kpp: "\33[5~"
kri: "\33[1;2A"
mc0: "\33[i"
mc4: "\33[4i"
mc5: "\33[5i"
meml: "\33l"
memu: "\33m"
op: "\33[39;49m"
rc: "\0338"
rev: "\33[7m"
ri: "\33M"
rin: "\33[5T"
rmacs: "\33(B"
rmam: "\33[?7l"
rmcup: "\33[?1049l"
rmir: "\33[4l"
rmkx: "\33[?1l\33>"
rmso: "\33[27m"
rmul: "\33[24m"
rs1: "\33c"
rs2: "\33[!p\33[?3;4l\33[4l\33>"
sc: "\0337"
setab: "\33[45m"
setaf: "\33[35m"
sgr0: "\33(B\33[m"
smacs: "\33(0"
smam: "\33[?7h"
smcup: "\33[?1049h"
smir: "\33[4h"
smkx: "\33[?1h\33="
smso: "\33[7m"
smul: "\33[4m"
tbc: "\33[3g"
u6: "\33[5;0R"
u7: "\33[6n"
u8: "\33[?1;2c"
u9: "\33[c"
vpa: "\33[6d"

termtrace(){( strace -s 1000 -e write tput $@ 2>&2 2>&1 ) | grep -o '"[^"]*"';}

AskApache · 2010-03-17 08:53:41 0

intercept stdout/stderr of another process or disowned process

Useful to recover a output(stdout and stderr) "disown"ed or "nohup"ep process of other instance of ssh. With the others options the stdout / stderr is intercepted, but only the first n chars. This way we can recover ALL text of stdout or stderr Show Sample Output
This is sample output - yours may be different.
```
{ i=0; while sleep 1; do echo -e "writing a long line to stdout 1 [AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA] 2 [BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB] 3 [CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC] \nline2 == var i=$((i++))";done; } > /dev/null & PID=$!
```
3

strace -e write=1,2 -p $PID 2>&1 | sed -un "/^ |/p" | sed -ue "s/^.\{9\}$.\{50\}$.\+/\1/g" -e 's/ //g' | xxd -r -p

glaudiston · 2010-10-06 19:37:39 1
easily strace all your apache processes

Will open strace on all apache process, on systems using sbin/apache (debian) or sbin/httpd (redhat), and will follow threads newly created.
This is sample output - yours may be different.
3

ps auxw | grep -E 'sbin/(apache|httpd)' | awk '{print"-p " $2}' | xargs strace -F

gormux · 2016-08-04 10:59:58 0
Locate config files of the program

Locate config files of the program. May not be used for interactive programs like vim.
This is sample output - yours may be different.
1

strace -e open zim 2>&1 1>/dev/null | fgrep ~ | fgrep -v "= -1" | cut -d'"' -f2

unixmonkey17435 · 2011-01-31 22:46:51 0
easily strace all your apache processes

This version also attaches to new processes forked by the parent apache process. That way you can trace all current and *future* apache processes.
This is sample output - yours may be different.
1

ps auxw | grep sbin/apache | awk '{print"-p " $2}' | xargs strace -f

msealand · 2013-02-19 19:14:57 0

Advanced python tracing

Trace python statement execution and syscalls invoked during that simultaneously Show Sample Output

strace python -m trace --trace myprog.py | grep -v 'write(1,'

roolebo · 2016-05-27 21:01:01 0

See what apache is doing without restarting it in debug mode
This is sample output - yours may be different.
0

pidof httpd | sed 's/ / -p /g' | xargs strace -fp

daniele · 2011-06-28 09:53:19 0
change binary string readable
This is sample output - yours may be different.
0

# strace ... | perl -lne '@F=split(/\\/, $_);for(@F){push @ddd, sprintf("%x", oct("0" . $_))}END{shift @ddd; print pack("H*", join("", @ddd));}'

zwxajh · 2012-10-16 14:24:13 0
strace a program

How to figure out what a program is doing. -tt detailed timestamps -f also strace any child processes -v be very verbose, even with common structures -o write output to file -s N capture up to N characters of strings, rather than abbreviating with ...
This is sample output - yours may be different.
0

strace -ttvfo /tmp/logfile -s 1024 program

ryanchapman · 2013-07-06 08:19:29 0
easily strace all your apache *child* processes

On debian parent process is running as root, workers as www-data. You can run strace in backgroud, get its PID, curl your webpage, kill strace and read your stats.
This is sample output - yours may be different.
0

strace -c $(ps -u www-data o pid= | sed 's/^/-p/')

brablc · 2015-11-25 08:10:52 0
easily trace all Nginx processes

Nginx (and other webservers like Apache) can be awkward to trace. They run as root, then switch to another user once they're ready to serve web pages. They also have a "master" process and multiple worker processes. The given command finds the process IDs of all Nginx processes, joins them together with a comma, then traces all of them at once with "sudo strace." System trace output can be overwhelming, so we only capture "networking" output. TIP: to kill this complex strace, do "sudo killall strace". Compare with a similar command: http://www.commandlinefu.com/commands/view/11918/easily-strace-all-your-apache-processes Show Sample Output
This is sample output - yours may be different.
```
# grab an Nginx web page:
#     curl -so /dev/null localhost

[pid  1145] accept4(6, {sa_family=AF_INET, sin_port=htons(57358), sin_addr=inet_addr("127.0.0.1")}, [16], SOCK_NONBLOCK) = 10
[pid  1145] recvfrom(10, "GET / HTTP/1.1\r\nUser-Agent: curl"..., 1024, 0, NULL, NULL) = 73
[pid  1145] setsockopt(10, SOL_TCP, TCP_CORK, [1], 4) = 0
[pid  1145] sendfile(10, 11, [0], 612)  = 612
[pid  1145] setsockopt(10, SOL_TCP, TCP_CORK, [0], 4) = 0
[pid  1145] recvfrom(10, 0xa7e1c0, 1024, 0, 0, 0) = -1 EAGAIN (Resource temporarily unavailable)
[pid  1145] recvfrom(10, "", 1024, 0, NULL, NULL) = 0
```
0

sudo strace -e trace=network -p `pidof nginx | sed -e 's/ /,/g'`

shavenwarthog · 2016-01-28 18:48:16 0
strace to find out what files a process executes
This is sample output - yours may be different.
0

strace -f -e trace=process [command]

Raboo · 2016-07-12 12:27:56 0
easily strace all your apache processes
This is sample output - yours may be different.
0

strace -p "`pidof httpd`"

weirdan · 2016-07-28 01:34:55 0
Linux system calls of MySQL process
This is sample output - yours may be different.
0

strace -c -p $(pidof -s mysqld) -f -e trace=all

shantanuo · 2020-02-27 03:35:17 3
Find which config-file is read
This is sample output - yours may be different.
0

strace 2>&1 geany |grep geany.conf

knoppix5 · 2020-04-20 19:42:39 1

What's this?

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Make a thumbnail image of first page of a PDF.

convert is included in ImageMagick. Don't forget the [X] (where X is the page number). [0] is the first page of the PDF.

Update Ogg Vorbis file comments

The "vorbiscomment" utility lets you update information such as artist names and song and album tags in an Ogg Vorbis file. You can use this command to fix any mistakes that were made when ripping an album.

Show current working directory of a process

Set laptop display brightness

Run as root. Path may vary depending on laptop model and video card (this was tested on an Acer laptop with ATI HD3200 video). $ cat /proc/acpi/video/VGA/LCD/brightness to discover the possible values for your display.

mean color of an image

You can get the mean value for the colours in an image. Then you can determine, in general, how dark or bright is the image and run some other actions based on that. I'll recommend to readjust the brightness of the images using +sigmoidal-contrast option of imagemagick convert command.

Get AWS temporary credentials ready to export based on a MFA virtual appliance

You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Calculate days on which Friday the 13th occurs

Simply change the years listed in the first seq, and it will print out all the months in that span of years that have Friday the 13ths in them.

List upcoming events on google calendar

Requires googlecl (http://code.google.com/p/googlecl/) Even better when you wrap this in a script and allow the --date=STRING to be $1. Then you can type: whatson "next Thursday" The date string for UNIX date is very flexible. You can also add --cal "[regex]" to the end for multiple calendars.

Retrieve the size of a file on a server

- Where $URL is the URL of the file. - Replace the $2 by $3 at the end to get a human-readable size. Credits to svanberg @ ArchLinux forums for original idea. Edit: Replaced command with better version by FRUiT. (removed unnecessary grep)

Downsample mp3s to 128K

This will lower the quality of mp3 files, but is necessary to play them on some mobile devices.

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Commands using strace (25)

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