3.1 cat命令 cat是显示文本文件包含的所有内容的命令。通过cat --h查看该命令的参数列表: 根据上图所示,对cat命令使用的实例如下图所示: 3.2 more命令 cat命令主要缺点在于启动之后无法控制。未解决这个问题,开发人员创建了more,more命令显示文本文件,但是在显示完每页数据时停止。根据more --h查看more的参数使用说明
An crray is like a series of slots that hold values. Each slot is known as an element, and each element can be accessed via a numerical index. An array element can contain a string or a number, and you can use it just like any other variable. The indices for arrays start at 0 and...
environment variable is used. --no-iri turn off IRI support --local-encoding=ENC use ENC as the local encoding for IRIs --remote-encoding=ENC use ENC as the default remote encoding --unlink remove file before clobber --keep-badhash keep files with checksum mismatch (append .badhash) --...
time is `date`"# Use $() insteadcddir; process *;cd..;# Use subshells insteadecho$[1+2]# Use standard $((..)) instead of old $[]echo$(($RANDOM% 6))# Don't use $ on variables in $((..))echo"$(date)"# Useless use of echocat file | grep foo# Useless use of cat ...
命令替換 $(cat file) 可以用等價但是更快的方法 $(< file) 代替。 當使用舊式的反引號 ("``") 替換形式時,反斜槓只有其字面意義,除非 後面是 $, `, 或者是 \. 第一個前面沒有反 斜槓的反引號將結束命令替換。當使用 $(command) 形式時,括號中所有字符組成了整個命令;沒有被特殊處理的字 符。
git-cat-file(1) git-check-attr(1) git-check-ref-format(1) git-checkout-index(1) git-checkout(1) git-cherry-pick(1) git-cherry(1) git-citool(1) git-clean(1) git-clone(1) git-commit-tree(1) git-commit(1) git-config(1) git-count-objects(1) git-credential-cache--daemon(1)...
Alternative to the cat command.file_data="$(<"file")"Read a file to an array (by line)Alternative to the cat command.# Bash <4 IFS=$'\n' read -d "" -ra file_data < "file" # Bash 4+ mapfile -t file_data < "file"
In order to use nvm, node, and npm like normal, you can instead specify the special BASH_ENV variable, which bash sources when invoked non-interactively.# Use bash for the shell SHELL ["/bin/bash", "-o", "pipefail", "-c"] # Create a script file sourced by both interactive and ...
# set variable identifying the chroot you work in (used in the prompt below) if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then debian_chroot=$(cat /etc/debian_chroot) fi # set a fancy prompt (non-color, unless we know we "want" color) ...
命令替换 $(cat file) 可以用等价但是更快的方法 $(< file) 代替。 当使用旧式的反引号 ("``") 替换形式时,反斜杠只有其字面意义,除非 后面是 $, `, 或者是 \. 第一个前面没有反 斜杠的反引号将结束命令替换。当使用 $(command) 形式时,括号中所有字符组成了整个命令;没有被特殊处理的字 符。