commands and switches Flashcards
find [path] -name “[name]”
find files and subdirs
find [path] -type d -name “[dir]”
find subdirs
ldconfig –print-cache
Print the lists of directories and candidate libraries stored in the current cache. Pipe into grep to find if a particular library is installed and accessible.
type [cmd]
Find whether the given command is an alias, shell built-in, file, function, or keyword. Also displays path
type -t [cmd]
Show just type
type -p [cmd]
Show just path
type -a [cmd]
Show all info
du [paths]
Disk usage
du -h [path]
Disk usage in human readable form
strace -f [program]
Trace child processes
strace -o “filename”
Output to log
strace -p PID
Attach
strace trace=open
Show opened files
rename ‘s/[old regex]/[new regex]/’
Batch rename
rename ‘s/-//’ ./*
remove dashes in all names in current folder: (1st dash)
grep [path] -e [pattern]
Search for pattern in path
grep -r
recursive
grep -n
display line number
grep -w
search for whole word
grep -l
show just file names
[[ -a file ]]
Test if file/dir exists. Identical to -e
[[ -d file ]]
Test if directory exists
[[ -f file ]]
True if file exists and is a regular file.
[[ -e file ]]
Test if file/dir exists. Identical to -a
[[ -r file ]]
True if file exists and is readable
[[ -s file ]]
True if file exists and has a size greater than zero.
[[ -w file ]]
True if file exists and is writable
[[ -x file ]]
True if file exists and is executable
[[ file1 -nt file2
]]
True if file1 is newer than file 2
[[ file1 -ot file2 ]]
True if file1 is older than file2
[[ -v varname ]]
True if the shell variable varname is set (has been assigned a value).
[[ -z string ]]
True if the length of string is zero
[[ -n string ]]
True if the length of string is non-zero
[[ arg1 -eq arg2 ]]
Arithmetic are equal
[[ arg1 -ne arg2 ]]
Arithmetic not equal
[[ arg1 -lt arg2 ]]
Arithmetic less than
[[ arg1 -le arg2 ]]
Arithmetic less or equal
[[ arg1 -gt arg2 ]]
Arithmetic greater than
[[ arg1 -ge arg2 ]]
Arithmetic greater or equal
[[ arg1 == arg2 ]]
String equality
[[ arg1 != arg2 ]]
Strings different
[[ arg1 < arg2 ]]
String 1 is lexicographically before string 2
ls -l
long listing format
ls -A
Almost all files: with hidden, no ./..
ls -a
all files: hidden, ./..
tail -F some.log
Track while adding
rm -f
remove file force: no confirmation
file [full path]
auto detect file type
ldd [full path]
show static .so dependencies
wc
word count
wc -l
word count, just lines
lsof
list open files
lsof +D [path]
list open files within directory
lsof +r 5
list open files, refresh every 5 sec
ps
active processes by my user
ps -u guga
all active processes by user guga
uniq -c
Show count of unique entries in sorted input
sort [file]
sort lines
tcpdump -qns 0 -r [file]
dump pcap contents
- q: quiet, less protocol info
- n: don’t convert ip to names
- s [X]: snap X bytes of data from the packet. -s 0: don’t display the packet
- r: read [file]
grep -o
Print only matching parts of a matching line
grep -P
Pattern is a perl-compatible regex
xargs -n 1
–max-lines=1 : use at most 1 argument per command line
xargs -t
synonym to –verbose, show all commands
xargs -I % (capital i)
replace % with the input. Doesn’t have to use % as the replace-str
xargs -P 7
run at most 7 processes
find /tmp -name core -type f -print0 | xargs -0 /bin/rm -f
Find files named core in or below the directory /tmp and delete them, processing filenames in such a way that file or directory names containing spaces or newlines are correctly handled.
remote copy (directory)
scp -r username@from_host:/remote/directory/ /local/directory/
ls only folders
ls -d */
huh?
in htop, show open files
l
in htop, strace
s
processor bar colors in htop
Blue/green/red: low-pri/normal/kernel threads
Memory bar colors in htop
Green/blue/yellow: used/buffer/cache
in htop, show env
e
xargs show commands
–verbose, -t
xargs confirm each command separately
–interactive
