-n             do not output the trailing newline
-e             enable interpretation of backslash escapes
-E             disable interpretation of backslash escapes (default)
    --help     display this help and exit

cmd:trap

Normal usage

tmpf=tmp.$$
trap "rm -f $tmpf" 0
trap "exit 2" SIGHUP SIGINT SIGQUIT SIGTERM  # 1 2 3 15

cat > $tmpf
cat $tmpf ..

Manipulating

Trap set & show:

$ trap -p

$ trap 'rm semaphore' 0

$ trap 'rm semaphore' SIGINT

$ trap -p
trap -- 'rm semaphore' EXIT
trap -- 'rm semaphore' SIGINT

$ trap -l
 1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL
[..]

$ set -x

Press ^C:

$ ++ rm semaphore
rm: cannot lstat `semaphore': No such file or directory

Trap reset:

$ trap - SIGINT
+ trap - SIGINT

Press ^C again, no more traps:

cmd:sleep

Usage

In unix:

sleep 10

sleep 10 seconds

To execute a command after a certain amount of time:

(sleep 105; command)&


	sendf can't use this way (when user interaction is needed). Put it in foreground instead.

Linux special

sleep 2m

sleep 2 minutes

SUFFIX m for minutes, h for hours or d for days.

cmd:rm

-r Recursively remove directories and subdirectories in the argument list. -f Remove all files (whether write-protected or not) in a directory without prompting the user.

cmd:pidof

$ pidof emacs
1795 1506 1495

$ [ `/sbin/pidof nono` ] && echo aaa

$ [ `/sbin/pidof X` ] && echo aaa
aaa

cmd:dircmp

*Tags*: dir compare. compare directory.

cmd:script

script [-a] [-c COMMAND] [file]

For single command, you can use

script -c COMMAND

-c COMMAND
        Run the COMMAND rather than an interactive shell.  This makes it
        easy for a script to capture the output of a program that behaves
        differently when its stdout is not a tty.

cmd:most

Info

most - browse or page through a text file

Usage

most -ct4 +82 keymap.c

makes searches case sensitive, sets tabwidth to 4, and displays the file keymap.c starting at line 82.

Help

MOST version S4.8.1 Usage:
most [-1bckstvw] [+/string] [+line number] [+s] [+d] file...
where: -1:  assume VT100 terminal. (VMS only)
       -b:  Startup in binary mode.
       -c:  Make searches case sensitive.
       -k:  Kanji mode.
       -s:  Squeeze out excess blank lines.
       -t:  Display tabs as ^I.  If this option is immediately followed
              by an integer, the integer sets the tab width.
       -v:  Do not interpret backspace formatting characters.
       -w:  Wrap lines.
       -z:  No gunzip-on-the-fly.
       +/string:
            Search for string
       +line number
            Start up at specified line number.
       +d:  Allow file deletion.
       +s:  Secure Mode-- no edit, cd, shell, and reading files not
              already listed on the command line.